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Document:	AlphaServer DS20 Service Manual
Order Number:	EK-AS140-SV
Revision:	A01
Pages:	182
Original Filename:

OCR Text

AlphaServer DS20
Service Manual

Order Number:

EK–AS140–SV. A01

This manual is for anyone who services this system. It includes
troubleshooting information, configuration rules, and instructions for
removal and replacement of field-replaceable units.

Compaq Computer Corporation

Notice
The information in this publication is subject to change without notice.
COMPAQ COMPUTER CORPORATION SHALL NOT BE LIABLE FOR TECHNICAL
OR EDITORIAL ERRORS OR OMISSIONS CONTAINED HEREIN, NOR FOR
INCIDENTAL OR CONSEQUENTIAL DAMAGES RESULTING FROM THE
FURNISHING, PERFORMANCE, OR USE OF THIS MATERIAL.
This publication contains information protected by copyright. No part of this publication may be
photocopied or reproduced in any form without prior written consent from Compaq Computer
Corporation.
The software described in this document is furnished under a license agreement or
nondisclosure agreement and may be used or copied only in accordance with the terms of the
agreement.
© 1999 Digital Equipment Corporation.
All rights reserved. Printed in the U.S.A.
COMPAQ and the Compaq logo are trademarks or registered trademarks of Compaq Computer
Corporation. AlphaServer, DIGITAL, OpenVMS, and StorageWorks are trademarks or
registered trademarks of Digital Equipment Corporation. Microsoft, Windows, and Windows
NT are registered trademarks of Microsoft Corporation. UNIX is a registered trademark in the
U.S. and other countries, licensed exclusively through X/Open Company Ltd. Other product
names mentioned herein may be trademarks and/or registered trademarks of their respective
companies.
Digital Equipment Corporation now owned by Compaq Computer Corporation.
FCC Notice: The equipment described in this manual generates, uses, and may emit radio
frequency energy. The equipment has been type tested and found to comply with the limits for a
Class A digital device pursuant to Part 15 of FCC Rules, which are designed to provide
reasonable protection against such radio frequency interference. Operation of this equipment in
a residential area may cause interference, in which case the user at his own expense will be
required to take whatever measures are required to correct the interference.
Shielded Cables: If shielded cables have been supplied or specified, they must be used on the
system in order to maintain international regulatory compliance.
Warning! This is a Class A product. In a domestic environment this product may cause radio
interference, in which case the user may be required to take adequate measures.
Achtung! Dieses ist ein Gerät der Funkstörgrenzwertklasse A. In Wohnbereichen können bei
Betrieb dieses Gerätes Rundfunkstörungen auftreten, in welchen Fällen der Benutzer für
entsprechende Gegenmaßnahmen verantwortlich ist.
Avertissement! Cet appareil est un appareil de Classe A. Dans un environnement résidentiel,
cet appareil peut provoquer des brouillages radioélectriques. Dans ce cas, il peut être demandé à
l'utilisateur de prendre les mesures appropriées.

Contents
Preface

........................................................................... ix

Chapter 1

System Overview

1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.8.1
1.8.2
1.8.3
1.9
1.9.1
1.10
1.11
1.12
1.13
1.14
1.15

System Enclosure .....................................................................................1-2
Operator Control Panel and Drives ...........................................................1-4
System Consoles ......................................................................................1-6
System Architecture .................................................................................1-8
CPU Types.............................................................................................1-10
Memory .................................................................................................1-12
Memory Addressing and Data Location .................................................. 1-14
System Board.........................................................................................1-16
Cross-Bar Switch and System Components ...................................... 1-18
I/O Subsystem .................................................................................1-20
System Board Switchpacks ..............................................................1-22
Server Feature Module ........................................................................... 1-24
Power Control Logic .......................................................................1-26
Power Circuit and Cover Interlock..........................................................1-28
Power Supply.........................................................................................1-30
Power Up/Down Sequence .....................................................................1-32
TIG Bus .................................................................................................1-34
2
Maintenance Bus (I C Bus)..................................................................... 1-36
StorageWorks Drives.............................................................................. 1-38

Chapter 2
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.8.1
2.8.2
2.9

Troubleshooting

Troubleshooting During Power-Up ...........................................................2-2
Control Panel Display and Troubleshooting ..............................................2-4
Power-Up Display and Troubleshooting....................................................2-6
Running Diagnostics — Test Command ...................................................2-8
Testing an Entire System ..........................................................................2-9
Other Useful Console Commands ...........................................................2-11
Troubleshooting with LEDs.................................................................... 2-12
Compaq Analyze ....................................................................................2-14
Compaq Analyze Graphics Interface (GUI)...................................... 2-14
Description of the Error ................................................................... 2-16
Releasing Secure Mode ..........................................................................2-20

iii

Chapter 3
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9

Ibox Status Register - I_STAT..................................................................3-2
Memory Management Status Register – MM_STAT.................................3-3
Dcache Status Register – DC_STAT.........................................................3-5
Cbox Read Register..................................................................................3-7
Miscellaneous Register (MISC) ................................................................3-9
Device Interrupt Request Register (DIRn, n=0,1) .................................... 3-12
Pchip Error Register (PERROR).............................................................3-13
Failure Register ......................................................................................3-16
Function Register ................................................................................... 3-18

Chapter 4
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
4.10
4.11
4.12
4.13
4.14
4.15
4.16
4.17
4.18
4.19
4.20

Removal and Replacement

System Safety ..........................................................................................4-1
FRU List ..................................................................................................4-2
System Access .........................................................................................4-6
CPU Removal and Replacement ...............................................................4-8
Memory Module Removal and
Replacement ..................................4-10
System Board Removal and Replacement ............................................... 4-12
PCI/ISA Option Removal and Replacement ............................................ 4-14
Server Feature Module Removal and Replacement.................................. 4-16
Power Supply Removal and Replacement ............................................... 4-18
Power Harness Removal and Replacement.............................................. 4-20
Power Transition Module Removal and Replacement.............................. 4-22
Auxiliary Fan Removal and Replacement ............................................... 4-24
System Fan Removal and Replacement................................................... 4-26
Cover Interlock Removal and Replacement............................................. 4-28
Operator Control Panel Removal and Replacement ................................ 4-30
CD-ROM Removal and Replacement .....................................................4-32
Floppy Removal and Replacement.......................................................... 4-34
SCSI Disk Removal and Replacement .................................................... 4-36
StorageWorks Backplane Removal and Replacement .............................. 4-38
StorageWorks UltraSCSI Bus Extender Removal and Replacement......... 4-40

Appendix A
A.1
A.2
A.3
A.4
A.5
A.6

Error Registers

Halts, Console Commands, and Environment
Variables

Halt Button Functions.............................................................................. A-2
Using the Halt Button.............................................................................. A-3
Halt Assertion ......................................................................................... A-4
Summary of SRM Console Commands .................................................... A-6
Summary of SRM Environment Variables ............................................... A-8
Recording Environment Variables ......................................................... A-10

Appendix B
B.1
B.2
B.2.1
B.3
B.4
B.5

RCM Overview ....................................................................................... B-2
First-Time Setup ..................................................................................... B-3
Using RCM Locally or with a Modem on COM1 ............................... B-4
RCM Commands..................................................................................... B-5
Using the RCM Switchpack................................................................... B-10
Troubleshooting Guide .......................................................................... B-13

Appendix C
C.1
C.1.1
C.1.2
C.1.3
C.1.4
C.1.5

Managing the System Remotely

Firmware Update

Updating Firmware and Consoles ............................................................ C-2
Updating Firmware from the CD-ROM.................................................... C-4
Updating Firmware from Floppy Disk — Creating the Diskettes .............. C-8
Updating Firmware from Floppy Disk — Performing the Update ........... C-10
Updating Firmware from a Network Device........................................... C-14
LFU Commands.................................................................................... C-18

Examples
1–1
2–1
2–2
2–3
2–4
2–5
2–6
2–7
B–1
C–1
C–2
C–3
C–4
C–5
C–6
C–7

Show Memory............................................................................................ 1-15
Power-Up Display ........................................................................................2-6
Test Command Syntax..................................................................................2-8
Sample Test Command.................................................................................2-9
Show Power ............................................................................................... 2-11
Show Memory............................................................................................ 2-11
Compaq Analyze Error Report.................................................................... 2-16
Releasing/Reestablishing Secure Mode ....................................................... 2-20
Invoking and Leaving RCM Locally ............................................................ B-4
Starting LFU from the SRM Console ........................................................... C-2
Booting LFU from the CD-ROM ................................................................. C-3
Updating Firmware from the CD-ROM ........................................................ C-4
Creating Update Diskettes on an OpenVMS System ..................................... C-9
Updating Firmware from the Floppy Disk .................................................. C-10
Selecting AS1400FW to Update Firmware from the Internal Floppy Disk... C-13
Updating Firmware from a Network Device ............................................... C-14

Figures
1-1
1-2
1-3
1-4
1-5
1-6
1-7
1-8
1-9
1-10
1-11
1-12
1-13
1-14
1-15
1-16
1-17
1-18
1-19
1-20
2-1
2-2
2-3
4-1
4-2
4-3
4-4
4-5
4-6
4-7
4-8
4-9
4-10
4-11
4-12
4-13
4-14
4-15
4-16
4-17
4-18

System Enclosure .........................................................................................1-2
Cover Interlock Circuit.................................................................................1-3
Control Panel Assembly ...............................................................................1-4
Block Diagram .............................................................................................1-8
CPU Module Placement ............................................................................. 1-10
Memory Placement .................................................................................... 1-12
Contents of DIMMs ................................................................................... 1-14
Memory Configuration............................................................................... 1-15
System Board............................................................................................. 1-16
Cross-Bar Switch Data Block Diagram ....................................................... 1-18
PCI Block Diagram .................................................................................... 1-20
Switchpack Location .................................................................................. 1-22
Server Feature Module ............................................................................... 1-24
Power Control Logic .................................................................................. 1-26
Power Circuit Diagram............................................................................... 1-28
Back of Power Supply and Location ........................................................... 1-30
Power Up/Down Sequence Flowchart......................................................... 1-32
TIG Bus Block Diagram............................................................................. 1-34
2
I C Bus Block Diagram .............................................................................. 1-36
StorageWorks Drive Location .................................................................... 1-38
Control Panel and LCD Display....................................................................2-4
CPU and Server Feature Module LEDs....................................................... 2-12
Compaq Analyze Graphics Interface........................................................... 2-14
Some of the FRU Locations..........................................................................4-2
Accessing the System ...................................................................................4-6
Removing CPU Module ...............................................................................4-8
Removing Memory .................................................................................... 4-10
Removing System Board ............................................................................ 4-12
Removing PCI/ISA Option......................................................................... 4-14
Removing Server Feature Module .............................................................. 4-16
Removing Power Supply ............................................................................ 4-18
Removing Power Harness........................................................................... 4-20
Removing Power Transition Module .......................................................... 4-22
Remove Auxiliary Fan Removal................................................................. 4-24
Removing System Fan................................................................................ 4-26
Removing Cover Interlock.......................................................................... 4-28
Removing OCP .......................................................................................... 4-30
Removing CD-ROM .................................................................................. 4-32
Removing Floppy....................................................................................... 4-34
Removing StorageWorks Disk.................................................................... 4-36
Removing StorageWorks Backplane........................................................... 4-38

4-19
B-1
B-2
C–1

Removing StorageWorks UltraSCSI Bus Extender...................................... 4-40
RCM Connections ...................................................................................... B-3
Location of RCM Switchpack on Server Feature Module .......................... B-10
Starting LFU from the AlphaBIOS Console................................................. C-2

Tables
1-1 PCI Slot Numbering.................................................................................... 1-21
1-2 Switchpack 2............................................................................................... 1-23
1-3 Switchpack 3............................................................................................... 1-23
1-4 Remote Control Switch Functions ............................................................... 1-25
2-1 Control Panel Display ...................................................................................2-5
2-2 Types of Errors ........................................................................................... 2-19
3-1 Ibox Status Register ......................................................................................3-2
3-2 Memory Management Status Register............................................................3-4
3-3 Dcache Status Register..................................................................................3-6
3-4 Cbox Read Register.......................................................................................3-7
3-5 Miscellaneous Register................................................................................ 3-10
3-6 Device Interrupt Request Register ............................................................... 3-12
3-7 Pchip Error Register.................................................................................... 3-14
3-8 Failure Register........................................................................................... 3-17
3-9 Function Register ........................................................................................ 3-19
4-1 Field-Replaceable Unit Part Numbers ............................................................4-3
A-1 Results of Pressing the Halt Button............................................................... A-2
A-2 Summary of SRM Console Commands......................................................... A-6
A-3 Environment Variable Summary................................................................... A-8
A-4 Environment Variables Worksheet.............................................................. A-10
B-1 RCM Command Summary............................................................................ B-5
B-2 RCM Status Command Fields....................................................................... B-9
B-3 RCM Troubleshooting ................................................................................ B-13
C–1 File Locations for Creating Update Diskettes on a PC.................................... C-8
C–2 LFU Command Summary ........................................................................... C-18

vii

Preface

Intended Audience
This manual is written for the customer service engineer.

Document Structure
This manual uses a structured documentation design. Topics are organized into small
sections for efficient online and printed reference. Each topic begins with an abstract,
followed by an illustration or example, and ends with descriptive text.
This manual has four chapters and three appendixes, as follows:
•

Chapter 1, System Overview, introduces the Compaq AlphaServer DS20
system. It describes each system component.

•

Chapter 2, Troubleshooting, describes troubleshooting during power-up and
booting, as well as the test command.

•

Chapter 3, Error Registers, describes the error registers used to hold error
information.

•

Chapter 4, Removal and Replacement, describes removal and replacement
procedures for field-replaceable units (FRUs).

•

Appendix A, Halts, Console Commands, and Environment Variables,
summarizes the commands used to examine and alter the system configuration.

•

Appendix B, Managing the System Remotely, describes how to use the Remote
Console Manager (RCM) to monitor and control the system remotely.

•

Appendix C, Firmware Update, describes how to update system firmware.

Documentation Titles
Table 1 lists books in the documentation set.

Table 1 AlphaServer DS20 Documentation
Title

Order Number

User and Installation Documentation Kit

QZ–014AA–G8

User’s Guide

EK–AS140–UG

Basic Installation

EK–AS140–IN

Service Information
Service Manual

EK–AS140–SV

Information on the Internet
Using a Web browser you can access the AlphaServer InfoCenter at:
http://www.digital.com/info/alphaserver/products.html
Access the latest system firmware either with a Web browser or via FTP as follows:
ftp://ftp.digital.com/pub/Digital/Alpha/firmware/
Interim firmware released since the last firmware CD is located at:
ftp://ftp.digital.com/pub/Digital/Alpha/firmware/interim/

Chapter 1
System Overview
The Compaq AlphaServer DS20 system consists of up to two CPUs, up to 4 Gbytes of
memory, 6 I/O slots, and up to 7 SCSI storage devices. AlphaServer DS20 systems
can be mounted in a standard 19” rack.
AlphaServer DS20 systems support OpenVMS, Compaq Tru64 UNIX, Windows NT,
and Linux.
Topics in this chapter include the following:
•

System Enclosure

•

Operator Control Panel and Drives

•

System Consoles

•

System Architecture

•

CPU Types

•

Memory

•

Memory Addressing and Data Location

•

System Board

•

Server Feature Module

•

Power Circuit and Cover Interlock

•

Power Supply

•

Power Up/Down Sequence

•

TIG Bus

•

Maintenance Bus (I2C Bus)

•

StorageWorks Drives

System Overview 1-1

1.1

System Enclosure

The system has up to two CPU modules and up to 4 Gbytes of memory. A single
fast wide UltraSCSI StorageWorks shelf provides up to 128 Gbytes of storage.

Figure 1-1 System Enclosure

4
1

2
6

5
PKW-1402-98

1-2

AlphaServer DS20 Service Manual

The numbered callouts in Figure 1-1 refer to the system components.

➊ System card cage, which holds the system board and the CPU, memory, and
system I/O.

➋ PCI/ISA section of the system card cage.
➌ Operator control panel assembly, which includes the control panel, the LCD
display, and the floppy drive.

➍ CD-ROM drive.
➎ Cooling section containing two fans and the server feature module.
➏ StorageWorks shelf.
Cover Interlock
The system has a single cover interlock switch tripped by the top cover.

Figure 1-2 Cover Interlock Circuit
Power
Supply
Server Feature Module

Cover
Interlock
Push button
ON/OFF

Switch
pack

OCP
DC_ENABLE_L

OCP
Connector

Cover
Interlock
Switch

PK1405-99

NOTE: The cover interlock must be engaged to enable power-up.
To override the cover interlock, use a suitable object to close the interlock circuit.
Disk damage will result if the system is run with the top cover off.

System Overview 1-3

1.2

Operator Control Panel and Drives

The control panel includes the On/Off, Halt, and Reset buttons and an LCD
display.

Figure 1-3 Control Panel Assembly

CD-ROM
Floppy
OCP Display
1

PKW-0501-97

OCP display. The OCP display is a 16-character LCD that indicates status during
power-up and self-test. While the operating system is running, the LCD displays the
system type. Its controller is on the XBUS.
CD-ROM. The CD-ROM drive is used to load software, firmware, and updates. Its
controller is on PCI1 on the PCI backplane on the system board.
Floppy disk. The floppy drive is used to load software and firmware updates. The
floppy controller is on the XBUS on the PCI backplane on the system board.

1-4

AlphaServer DS20 Service Manual

➊

On/Off button. Powers the system on or off. When the LED to the right of the
button is lit, the power is on. The On/Off button is connected to the power
supplies through the system interlock and the RCM logic.

➋

Reset button. Initializes the system.

➌

Halt button. When the Halt button is pressed, different results are manifest
depending upon the state of the machine.
The major function of the Halt button is to stop whatever the machine is doing
and return the system to the SRM console.
To get to the SRM console, for systems running OpenVMS or Compaq Tru64
UNIX, press the Halt button.
To get to the SRM console, for systems running Windows NT, press the Halt
button and then press the Reset button. (Pressing the Halt button when the
system is running Windows NT causes a “halt assertion” flag to be set in the
firmware. When Reset is pressed, the console reads the “halt assertion” flag and
ignores environment variables that would cause the system to boot.)
The function of the Halt button is complex; it depends upon the state of the
machine when the button is pressed. See Section B.1 for a full discussion of the
Halt button.

System Overview 1-5

1.3

System Consoles

There are two console programs: the SRM console and the AlphaBIOS console.

SRM Console Prompt
On systems running the Compaq Tru64 UNIX or OpenVMS operating system, the
following console prompt is displayed after system startup messages are displayed, or
whenever the SRM console is invoked:
P00>>>
NOTE: The console prompt displays only after the entire power-up sequence is
complete. This can take up to several minutes if the memory is very large.
AlphaBIOS Boot Menu
On systems running the Windows NT operating system, the Boot menu is displayed
when the AlphaBIOS console is invoked:

1-6

AlphaServer DS20 Service Manual

SRM Console
The SRM console is a command-line interface used to boot the Compaq Tru64 UNIX
and OpenVMS operating systems. It also provides support for examining and
modifying the system state and configuring and testing the system. The SRM console
can be run from a serial terminal or a graphics monitor.
AlphaBIOS Console
The AlphaBIOS console is a menu-based interface that supports the Microsoft
Windows NT operating system. AlphaBIOS is used to set up operating system
selections, boot Windows NT, and display information about the system configuration.
The ISA Configuration Utility and the RAID Standalone Configuration Utility are run
from the AlphaBIOS console. AlphaBIOS runs on either a serial terminal or graphics
terminal. Windows NT requires a graphics monitor.
Environment Variables
Environment variables are software parameters that define, among other things, the
system configuration. They are used to pass information to different pieces of
software running in the system at various times. The os_type environment variable,
which can be set to VMS, UNIX, or NT, determines which of the two consoles is used.
The SRM console is always brought into memory, but AlphaBIOS is loaded if os_type
is set to NT and the Halt LED is not lit.
Refer to Appendix A of this guide for a list of the environment variables used to
configure a system.
Refer to your system User’s Guide for information on setting environment variables.
Most environment variables are stored in the NVRAM area of the flash ROM on the
system board. It is recommended that you keep a record of the environment variables
for each system that you service. Some environment variable settings are lost when a
module is swapped and must be restored after the new module is installed. Refer to
Appendix A for a convenient worksheet for recording environment variable settings.

System Overview 1-7

1.4

System Architecture

An Alpha microprocessor chip is used in this system. The CPU, memory, and the
I/O modules are physically connected to the system board and logically connected
through a switch-based interconnect implemented in a cross-bar switch chipset.

Figure 1-4 Block Diagram
Command, Address, and Control lines for each Memory Array

C chip
Control lines for D chips
Probe/
Addr.

Probe/
Addr.

CAPbus

P chip

64 bit PCI

P chip
64 bit PCI

CMD/
Addr.

PAD
Bus

CPU 1
(optional)

Up to 2
Memory
Banks

CMD/
Addr.

CPU 0

CPU
Data
Bus

Memory
Data
Bus
8 D chips

1 or 2
Memory
Banks

B cache
B cache
PKW1400-98

1-8

AlphaServer DS20 Service Manual

The AlphaServer DS20 is a switch-based interconnect system; it uses a cross-bar
switch chipset that allows data to move directly from place to place in the system. The
CPU, memory, and I/O devices physically connect to the system board and each has
one or two logical connections to the switch. The arrows on the block diagram shown
in Figure 1-4 indicate the flow of data, command/address, and control signals.
On the system board is:
•

A system switch consisting of a control chip (C-chip) and 8 data chips (D-chips)

•

Three buses to the D-chips: the memory data bus, the CPU data bus, and the
P-chip address and data bus (PAD bus)

•

One bus from the C-chip to the P-chips (CAP bus)

•

Two 60 command/address and control connections between each CPU and the
C-chip: the command/address line from the CPUs to the C-chip and the probe
address lines from the C-chip to the CPUs

•

A TIG bus connected to the C-chip

•

Control lines from the C-chip to the D-chips

•

Control, timing, and address lines from the C-chip to each memory array

•

Two 64-bit PCI buses with three PCI option slots each

•

One ISA bus bridged on PCI0 and two SCSI ports (unused at FRS) also on PCI0
(If an ISA option is used, PCI 1 slot 9 cannot be used for a PCI option.)

•

One ISA to XBUS bridge to the built-in XBUS options

A fully configured pedestal system can have two CPUs, sixteen DIMMs, a total of six
I/O options, and seven 18 Gbyte UltraSCSI disks. Maximum memory is 4 Gbytes.
The I/O options can be all PCI options or five PCI options and a single ISA option.
Other major lines in the system are used for command, addresses, and control.
For information on CPUs, see Section 1.5.
For information on memory, see Sections 1.6 and 1.7.
There are two 64-bit PCI buses connected to the cross-bar switch chipset by two PAD
buses and a single CAP bus. Each bus has three PCI slots for I/O devices. PCI bus 0
has an ISA bridge and a SCSI adapter with two ports (not used) embedded on the bus.
A single ISA slot is available on PCI bus 0 that, when used, eliminates the use of one
PCI slot on PCI bus 1.
Logic and sensors on the system feature module monitor power status and the system
environment (temperature and fan speeds).

System Overview 1-9

1.5

CPU Types

There is a single CPU variant.

Figure 1-5 CPU Module Placement

DIMM Slots

1
3
1
3
0
2
0
2

CPU 0
D
Chip

D
Chip

C
Chip

D
Chip

2
0
2
0
3
1
3
1

CPU 1

P
Chip

PCI 0 Slot 7
PCI 0 Slot 8
PCI 0 Slot 9
PCI 1 Slot 7
PCI 1 Slot 8
PCI 1 Slot 9
ISA Slot
PKW1401A-98

1-10

AlphaServer DS20 Service Manual

Alpha Chip Composition
The Alpha 21264 chip uses 0.35 micron chip technology, has a transistor count of 15.2
million, consumes 50 watts of power, and is air cooled (a fan is on the chip). The
default cache system is write-back.
Chip Description
Unit

Description

Instruction
Execution

64-Kbyte I-cache
4-way execution; four integer units, two of which can perform
memory address calculations for load and store instructions;
dedicated units for floating-point add, multiply, divide, and
square root operations.
Merge logic, 64-Kbyte write-through first-level data cache,
bus interface unit that consists of two ports, one a 16-byte Bcache port and the other an 8-byte system port.

Memory

CPU Variants
Module Variant

Clock Frequency

Onboard Cache

KN310-Ax

500 MHz

4 Mbytes

CPU Configuration Rules
•

The first CPU must be in CPU slot 0.

•

Both CPUs must have the same Alpha chip clock speed selected.

Module LEDs
LED Name

Description (read LEDs from right to left on the
module)

2V_PWRGOOD_LED

Normally on. Indicates the presence of 2.XV.

SROM_CLK_LED

Normally off. Toggles on and off rapidly during the
SROM load phase.

DC_OK_LED

Normally on. Indicates the presence of DC_OK.

CPU_SELF_TEST_LED

Normally on. Indicates the status of self-test. If the LED
is off, there was an error or timeout after the SROM load.

System Overview 1-11

1.6

Memory

Memory consists of up to four memory options, each consisting of four DIMMs.
There are four option variants: 128 Mbytes, 256 Mbytes, 512 Mbytes, and 1
Gbyte.

Figure 1-6 Memory Placement

DIMM Slots

1
3
1
3
0
2
0
2

CPU 0
D
Chip

D
Chip

C
Chip

D
Chip

2
0
2
0
3
1
3
1

CPU 1

P
Chip

PCI 0 Slot 7
PCI 0 Slot 8
PCI 0 Slot 9
PCI 1 Slot 7
PCI 1 Slot 8
PCI 1 Slot 9
ISA Slot
PKW1401B-98

1-12

AlphaServer DS20 Service Manual

Memory Variants
Memory is organized on two 256 plus ECC bit buses. Each bus can hold up to two
memory banks (a memory option) made up of four DIMM modules. Memory can be
configured from a minimum of 128 Mbytes (1 MS340-BA) to 4 Gbytes (4 MS340EA). All memory is synchronous.
DRAM
Option

Size

Module

Type

Number/
option

MS340-BA
MS340-CA
MS340-DA
MS340-EA

128 MB
256 MB
512 MB
1 GB

54-25066-BA
54-25053-BA
54-25941-KA
54-25941-BA

Synch.
Synch.
Synch.
Synch.

36
36
36
36

Size

4 x 32MB
4 x 64MB
4 x 128MB
4 x 256MB

Memory Operation
Two 256-bit memory buses transfer data between the cross-bar chipset switch and
main memory. Each DIMM bank, made up of four DIMM modules, provides the data,
or 256 bits plus 32 ECC bits, of the 32 bytes transferred. Two modules in the bank
provide the odd bytes of data, and the other two modules provide the even bytes of
data.
Memory Configuration Rules
In a system, memories of different sizes are permitted, but:
•

A memory option consists of four DIMMs all of which must be the same size.

•

Convention places the largest memory option in slots marked 0 on the system
board. See Figure 1-6.

•

Memory options must be installed in slots designated for each bank. The first
bank goes into slots marked 0, the second bank into slots marked 1, and so on.

System Overview 1-13

1.7

Memory Addressing and Data Location

Memory addressing is contiguous beginning with memory bank 0. The first
address of each bank is one above the ending address of the previous bank.
Data is located in DIMMs as described by Figure 1-7.

Figure 1-7 Contents of DIMMs

DIMM Slots

DIMM Contains
Bank 1 even bytes 0, 2, 4, 6, 8, 10, 12, 14
Bank 3 even bytes 0, 2, 4, 6, 8, 10, 12, 14
Bank 1 even bytes 16, 18, 20, 22, 24, 26, 28, 30
Bank 3 even bytes 16, 18, 20, 22, 24, 26, 28, 30
Bank 0 even bytes 0, 2, 4, 6, 8, 10, 12, 14
Bank 2 even bytes 0, 2, 4, 6, 8, 10, 12, 14
Bank 0 even bytes 16, 18, 20, 22, 24, 26, 28, 30
Bank 2 even bytes 16, 18, 20, 22, 24, 26, 28, 30

D
Chip

C
Chip

D
Chip

Bank 2 odd bytes 17, 19, 21, 23, 25, 27, 29, 31
Bank 0 odd bytes 17, 19, 21, 23, 25, 27, 29, 31
Bank 2 odd bytes 1, 3, 5, 7, 9, 11, 13, 15
Bank 0 odd bytes 1, 3, 5, 7, 9, 11, 13, 15
Bank 3 odd bytes 17, 19, 21, 23, 25, 27, 29, 31
Bank 1 odd bytes 17, 19, 21, 23, 25, 27, 29, 31
Bank 3 odd bytes 1, 3, 5, 7, 9, 11, 13, 15
Bank 1 odd bytes 1, 3, 5, 7, 9, 11, 13, 15

DIMM Slots
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AlphaServer DS20 Service Manual

Memory Addressing
The first address of each bank is one above the ending address of the previous bank.
Example 1–1 and Figure 1-8 show the starting address of each memory bank using
either the SRM console or AlphaBIOS.

Example 1–1 Show Memory
P00>>> show memory
Array #
------0
1
2
3

Size
---------128 MB
128 MB
128 MB
128 MB

Base Addr
--------000000000
008000000
010000000
018000000

Total Bad Pages = 0
Total Good Memory = 512 MBytes

P00>>>

Figure 1-8 Memory Configuration
Display System Configuration
Systemboard Configuration
Hard Disk Configuration
PCI Configuration
SCSI Configuration
ISA Configuration
Memory Configuration
Integrated Peripherals

F1= Help

System Memory Configuration
Bank 0: 128 MB (32 MB per DIMM) -- Starting Address = 0x00000000
Bank 1: 128 MB (32 MB per DIMM) -- Starting Address = 0x80000000
Bank 2: 128 MB (32 MB per DIMM) -- Starting Address = 0x10000000
Bank 3: 128 MB (32 MB per DIMM) -- Starting Address = 0x18000000

ESC =Exit
DIMM Contents
Figure 1-7 shows the data contents of each DIMM in memory. Odd data bytes are in
DIMMs below the cross-bar switch chipset, and the even data bytes are in the DIMMs
above the cross-bar switch chipset.

System Overview 1-15

1.8

System Board

The system board contains five major logic sections performing five major
system functions.

Figure 1-9
Even bytes
of all memory
banks

System Board
1
3
1
3
0
2
0
2

I/O
Connectors

Odd bytes
of all memory
banks

3 V Power
& Misc 3V

CPU 0
D
Chip

D
Chip

C
Chip

D
Chip

2
0
2
0
3
1
3
1

CPU 1

P
Chip

TIG
Pal

PCI 0 Slot 7
SCSI
Connectors

PCI 0 Slot 8

Flash
ROM

PCI 0 Slot 9
PCI 1 Slot 7

SCSI
CTRL

PCI 1 Slot 8
PCI 1 Slot 9
ISA Slot

ISA
Bridge
Junk I/O

5 V Power
Speaker
Connector
RCM
Connector

Battery

Floppy
Connector
IDE
Connector
PK1491-98

1-16

AlphaServer DS20 Service Manual

Three major sections on the system board are:
•

The cross-bar switch chipset and the system components attached to it (CPU(s),
memory, PCI chips, and the TIG bus)

•

The power connections and voltage regulator

•

The I/O subsystem

System Overview 1-17

1.8.1 Cross-Bar Switch and System Components
The cross-bar switch chipset consists of a single control chip, the C-chip, and
eight data chips, the D-chips. Into and out of the D-chips are two system buses to
CPUs, two PAD buses to PCI chips, and two memory data buses that connect to
up to four memory banks.

Figure 1-10 Cross-Bar Switch Data Block Diagram

CAP Bus

3FKLS

,2'HYLFHV

ELW3&,

,2'HYLFHV

3$'%XV

ELW

%FDFKH

FKLS

3$'%XV

TIG Bus

3FKLS
ELW3&,

TIG
PAL

Interrupts

ELW

&38

6\V'DWD

%XV
'
'
%FDFKH

'
&38

6\V'DWD
%XV

'
'
'

0HPRU\'DWD%XV

0HPRU\EDQN

0HPRU\'DWD%XV

0HPRU\EDQN

PK1489-98

1-18

AlphaServer DS20 Service Manual

Each type of bus in the system is unique:
•

The two memory data buses operate in 256-bit mode passing two hex words (32
bytes) of data between memory and the D-chips per cycle. The bus operates at
83.3 MHz.

•

The two CPU data buses operate in “64-bit mode” passing a quadword (8 bytes)
of data between CPU and the D-chips per cycle. Though the CPU data bus is
narrower than the memory data bus, it operates at four times the speed of the
memory data bus at 333 MHz.

•

The single CAP bus is a 24-bit wide bidirectional bus that carries commands and
addresses and is also used for transmitting data to and from the C-chip CSRs and
the TIG bus.

•

The two PAD buses operate in 32-bit mode passing 8 nibbles per cycle. Two
cycles are required to pass 8 bytes of data. The PAD bus runs at 83.3 MHz.

•

The TIG bus handles flash ROM data (system diagnostics and console programs)
and system interrupts.

The cross-bar switch is controlled by the C-chip which synchronizes, along with the
clock, the D-chips, the CPUs, memory, and the P-chips. Figure 1-10 shows the major
data paths through the system.
The C-chip contains:
•

Buffers for requests for the P-chips (shared), and each CPU

•

Request queues for each memory bank

•

A CPU interface for probe and fill requests and issues

•

A P-chip interface controller and bridge between PCI commands and addresses
and CPU PIO commands and addresses

•

D-chip controllers, one for the PAD bus and one for everything else

The D-chip contains:
•

Queues to and from the P-chip, to and from the CPUs, and to and from memory

•

Control from the C-chip

The P-chip contains:
•

Upstream (away from the PCI) and downstream (toward the PCI) data queues

•

Upstream and downstream address queues

•

An upstream address state machine for DMA and peer-to-peer reads and writes

•

A scatter/gather table for direct mapped and scatter/gather DMA memory access

System Overview 1-19

1.8.2 I/O Subsystem
The I/O subsystem consists of two 64-bit PCI buses. One has an embedded ISA
bridge, three PCI option slots, and a single ISA slot; the other bus has three PCI
option slots.

Figure 1-11 PCI Block Diagram

Crossbar
Switch

C Chip

8 D Chips
CAP Bus (24 bits)
PAD Bus (32 bits)

P Chip
PCI 0

1 ISA
Slot

P Chip
PCI 1
I/O ASIC

3&,%XV

Cypress Chip
(ISA Bridge,
IDE, KBRD,
MSE, USB)

ADAPTEC
Ultra SCSI
Controller
(2 ports)

COM1
COM2

Floppy

PCI-1 Bus

Parallel
Port
PCI-1
3 64-bit slots

PCI-0
3 64-bit slots

PK1494-98

1-20

AlphaServer DS20 Service Manual

Table 1-1 PCI Slot Numbering
Slot

PCI0

PCI1

PCI to ISA bridge

Adaptec SCSI

PCI slot

ISA

Shared

ISA device

logically

ISA device

physically

The logic for two PCI buses is on the system board.
•

PCI0 is a 64-bit bus with three PCI slots, a Cypress chip, and an Adaptec SCSI
controller. The Cypress chip is the PCI to ISA bus bridge and controls the
following: the keyboard, mouse, IDE bus, real-time clock, and the USB bus. (The
IDE bus and the USB bus are not used.) Connected to the ISA bus is an Adaptec
UltraSCSI controller with two ports (also not used).

•

PCI1 is a 64-bit bus with three PCI slots.

The cable connector to the floppy is on the system board. Connectors for the mouse,
keyboard, and COM2 are on the bulkhead and are connected directly to the Cypress
chip. The connector for COM1 is also on the bulkhead, but its path is from the
Cypress chip to the RCM connector out to the server feature module and back through
the RCM connector and then to the bulkhead. The path to the OCP is also carried
through the RCM connector to the server feature module and then on to the OCP.

System Overview 1-21

1.8.3 System Board Switchpacks
There are two switchpacks on the system board. They control the writing of the
flash ROM and the speed of the crossbar switch among other things.

Figure 1-12 Switchpack Location
Off

fsb
coa
cob
mdb
sp0

1
2
3
4
5
6
7
8

CPU 0
D
Chip
D
Chip

CPU 1

sp1
sp2
pby
SW2

P
Chip

Off

System Board

SW2
SW3

On
cn7
cn6
cn5
cn4
cn3
cn2
spr

1
2
3
4
5
6
7
8

flash_wr
SW3
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1-22

AlphaServer DS20 Service Manual

Figure 1-12 shows the location of the switchpacks and Table 1-2 and Table 1-3
describe what each switch controls.

Table 1-2 Switchpack 2
Switch

1
2
3
4
5
6
7
8

Description

Fail safe boot. Off (default) = normal boot. On = boot the fail safe booter
Reserved. Must be off.
Reserved. Must be off.
Reserved. Must be off.
Switches 5, 6, and 7 create a field that defines the speed at which the cross
bar switch runs. Switches 5 and 6 are on and switch 7 is off.
AlphaBIOS Password bypass: Off (default) = Normal operation;
On = Bypass AlphaBIOS password

Table 1-3 Switchpack 3
Switch
1
2
3
4
5
6
7
8

Description
Reserved. Must be off.
Reserved. Must be off.
Reserved. Must be off.
Reserved. Must be on.
Reserved. Must be off.
Reserved. Must be off.
Reserved. Must be off.
Flash write protect: Off (default) = Write enable the flash ROM
On = Write disable the flash ROM

System Overview 1-23

1.9

Server Feature Module

The server feature module provides remote control operation of the system. A
four-switch switchpack enables or disables remote control features.

Figure 1-13 Server Feature Module

Power
Connector
RCM
Connector

Switchpack
Interlock
Connector
Sys Fan OK
CPU Fan OK
Temp OK

5 Vaux
Power OK

System Fan
Connectors
OCP
Connector

1-24

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AlphaServer DS20 Service Manual

The system allows both local and remote control. The remote control firmware and a
set of switches that enable or disable remote control features reside on the server
feature module.

Table 1-4 Remote Control Switch Functions
Switch

Condition

Function

1 EN RCM

On (default)
Off

Allows remote system control
Does not allow remote system control

2 Reserved

Reserved

3 RPD DIS

On
Off (default)

Disables remote power down
Enables remote power down

4 SET DEF

On
Off (default)

Resets the RCM microprocessor defaults
Allows use of conditions set by the user

The default settings allow complete remote control. The user would have to change the
switch settings to any other desired control.
See Appendix C for information on controlling the system remotely.
The server feature module connects to COM1 on the bulkhead so that its remote
console functions can be accessed. The RCM uses VAUX power provided by the
system power supplies.
The interlock circuit runs through the server feature module as does the path to the
OCP. See Section 1.1.

System Overview 1-25

1.9.1 Power Control Logic
The power control logic is on the server feature module.

Figure 1-14 Power Control Logic

Power
Connector
RCM
Connector

Switchpack
Interlock
Connector
Sys Fan OK
CPU Fan OK
Temp OK

5 Vaux
Power OK

Fan
Connectors
OCP
Connector

1-26

PK1492-98

AlphaServer DS20 Service Manual

The power control logic performs these functions:
•

Monitors system temperature and powers down the system 30 seconds after it
detects that internal temperature of the system is above the value of the
0
environment variable over_temp. Default = 55 C.

•

Monitors the system and CPU fans and powers down the system 30 seconds after
it detects a fan failure.

•

Provides some visual indication of faults through LEDs.

•

Provides I C interface for fans, power supplies, and temperature signals:

Power supply 0, 1: present

Power supply 0, 1: power OK

CPU fan 0, 1: OK

CPU 0, 1: present

Overtemp: Temp OK

System fan 0, 1: OK

Fan Kit OK

System Overview 1-27

1.10 Power Circuit and Cover Interlock
Power is distributed throughout the system and mechanically can be broken by
the On/Off switch, the cover interlock, or remotely through the RCM.

Figure 1-15 Power Circuit Diagram
Power
Supply
Server Feature Module

Cover
Interlock

Push button
ON/OFF
Switch
pack

OCP
DC_ENABLE_L

OCP
Connector

1-28

PK1493-98

AlphaServer DS20 Service Manual

Figure 1-15 shows the distribution of the power enable circuit through the system.
Opens in the circuit, or the RCM signal RCM_DC_EN_L, or a power supply detected
power fault causes interruption to the DC power applied to the system.
A failure anywhere in the circuit will result in the removal of DC power. A potential
failure is the relay used in the remote control logic to control the RCM_DC_EN_L
signal.
The cover interlock is located under the top cover between the system card cage and
the storage area. To override the interlock, place a suitable object in the interlock
switch that closes it.

System Overview 1-29

1.11 Power Supply
Two power supplies provide system power.

Figure 1-16 Back of Power Supply and Location

Power
Supply 1
Power
Supply 0

Current
share
+5V/Return

+5V/Return
+12V/Return

Misc.
Signal
+3.4V/Return

PK1495-98

1-30

AlphaServer DS20 Service Manual

Description
A single 675 watt power supply provides power to the system. A second power
supply (optional) provides redundant power.
Power Supply Features
•

88–132 and 176–264 Vrms AC input

•

675 watts output. Output voltages are as follows:

Output Voltage

Max. Voltage

Max. Current

+5.0

4.85

5.25

100

+3.3

3.18

3.48

100

+12

11.5

12.6

–12

–10.9

–13.2

4.9

5.4

1.5

+5 Vaux
•

Min. Voltage

Remote sense on +5.0V and +3.3V
+5.0V is sensed on the system board.
+3.3V is sensed on the system board.

•

Current share on +5.0V, +3.3V, and +12V.

•

3% regulation on +3.3V.

•

Fault protection (latched). If a fault is detected by the power supply, it will shut
down. The power supply faults detected are:
Fan Failure (overtemp)
Overvoltage
Overcurrent
Power overload

•

DC_ENABLE_L input signal starts the DC outputs.

•

SHUTDOWN_H input signal shuts the power supply off in case of a system fan,
or CPU fan failure, or an overtemp condition detected by the power control logic.

•

POK_H output signal indicates that the power supply is operating properly.

System Overview 1-31

1.12 Power Up/Down Sequence
System power can be controlled manually by the On/Off button on the OCP or
remotely through the RCM. The power-up/down sequence flow is shown below.

Figure 1-17 Power Up/Down Sequence Flowchart
Apply AC
Power

Vaux on

On-Off Button
RCM Enable OK
Interlock OK

Off

Off
On

On-Off
Button

Assert
DC_ENABLE_L
Power Supply
Starts

Disable Outputs
Deassert POK

Yes

Any
Faults
No

Assert
SHUTDOWN

Assert
POK

On
On-Off Button
DC_ENABLE_L

30 Second
Delay

Fan/Temp
OK
Yes
PK1409-99

1-32

AlphaServer DS20 Service Manual

Off

When AC is applied to the system, Vaux (auxiliary voltage) is asserted and is sensed
on the server feature module. If the On-Off Button is On, and RCM OK and Interlock
OK are asserted, the OCP asserts DC_ENABLE_L starting the power supplies. If
there is a hard fault on power-up, the power supplies shut down immediately;
otherwise, the power system powers up and remains up until the system is shut off or
the server feature module senses a fault. If a power fault is sensed, the signal
SHUTDOWN is asserted after a 30 second delay. Cycling the On-Off button can
restore the power. If the system powers up and shuts off in approximately 30 seconds,
the server feature module has sensed a fault and a fan (system or CPU) is likely
broken.

System Overview 1-33

1.13 TIG Bus
The Timing, Interrupt, and General bus (TIG) performs a number of functions;
it carries all system interrupts, timing signals and provides the path to the
diagnostic and console flash ROMs.

Figure 1-18 TIG Bus Block Diagram
CPU
Data
Bus
D Chips

CPU s

PAD
Bus
P Chip

Interrupt
data lines
CAP
Bus

C Chip

TIG Bus

Flash
ROM

Config
Registers
and
switchpack

IRQs

1-34

AlphaServer DS20 Service Manual

Figure 1-18 is a block diagram of the TIG bus implemented through the TIG chip.
Three system functions are carried out on this bus.
Flash ROM
The flash ROM containing the diagnostics, fail-safe loader, and console firmware sits
on the TIG bus. (This is different from the AS 1200 where the flash ROM sat on the
2
I C bus.) Still a good deal of logic has to function for the diagnostics to run.
Configuration Registers
Registers on the bus include interrupts, module information, and clock information.
Interrupts
System interrupts are passed through the TIG bus to the C-chip. The bus connects
directly to PCI slots and to onboard devices.

System Overview 1-35

1.14 Maintenance Bus (I C Bus)
2

There are two I C buses (referred to as the “I squared C bus”) in this system.
The internal maintenance bus is used to monitor system conditions scanned by
the power control logic on the server feature module, log error state and track
2
system configuration information. There is a private I C bus between memory
and the C-chip used to provide memory configuration information to the consoles
and operating systems.

Figure 1-19 I2C Bus Block Diagram

Server Feature
Module

C-Chip

NVRAM
PCL
Registers
1

Private
2
I C Bus

Thermom/
Thermostat

CPU 0

up to 4

Memory
Banks

System
Board

System

P-Chip 0

OCP
Controller

I C Bus
Controller

XBUS

ISA Bridge

I C Bus

1-36

AlphaServer DS20 Service Manual

PK1406-99

Monitor
2

The I C bus monitors the state of system conditions scanned by the power control
logic. There are two registers that the PC logic writes data to:
•

One records the state of the fans and power supplies and is latched when there is a
fault.

•

The other causes an interrupt on the I C bus when a CPU or system fan fails, an
overtemperature condition exists, or power supplied to the system changes from
N + 1 to N or from N to N +1.

The interrupt received by the I C bus controller and passed on to P-chip 0 alerts the
system of a power system event that may or may not cause a power shutdown. In the
event of imminent power loss the controller has 30 seconds to read the two registers
and store the information in the NVRAM on the server feature module. The SRM
console command show power reads these registers.
Fault Display
The OCP display is written through the I2C bus.

Error State
Error state is stored for power, fan, and overtemperature conditions on the I2C bus.
Configuration Tracking
Each CPU and each logical section of the system board (the PCI bridge, the PCI
backplane, the power control logic, the remote console manager), and the system
board itself has an EEPROM that contains information about the module that can be
written and read over the I2C bus. All EEPROMs contain the following information:
•

Module type

•

Module serial number

•

Hardware revision for the logical block

•

Firmware revision

System Overview 1-37

1.15 StorageWorks Drives
The system supports up to seven StorageWorks drives.

Figure 1-20 StorageWorks Drive Location

StorageWorks
Drives Shelf

1-38

PKW0514-97

AlphaServer DS20 Service Manual

The StorageWorks drives are to the right of the system cage. Up to seven drives fit
into the shelf. The system supports fast wide UltraSCSI disk drives. The RAID
controller is also supported. With an optional UltraSCSI Bus Splitter Kit, the
StorageWorks shelf can be split into two buses.

System Overview 1-39

Chapter 2
Troubleshooting
This chapter describes troubleshooting during power-up and booting. It also describes
the console test command and other service related console commands. A Compaq
Analyze example is also provided. The following topics are covered:
•

Troubleshooting During Power-Up

•

Control Panel Display and Troubleshooting

•

Power-Up Display and Troubleshooting

•

Running Diagnostics — Test Command

•

Testing an Entire System

•

Other Useful Console Commands

•

Troubleshooting with LEDs

•

Compaq Analyze

•

Releasing Secure Mode

Troubleshooting

2-1

2.1

Troubleshooting During Power-Up

Power or other problems can occur before the system is up and running.

Power Problem List
The system will halt/power off for the following reasons:
1.

A CPU fan failure

A system fan failure

An overtemperature condition

Power supply failure if the redundant power option is not present

Circuit beaker(s) tripped

AC problem

Interlock switch activation or failure

Environmental electrical failure or unrecoverable system fault with auto_action ev
= halt or boot

Cable failure

Indication of failure
•

LEDs on the server feature module indicate fan, overtemperature, and power
problem conditions.

•

Circuit breaker(s) tripped at the AC service panel.

•

There is no obvious indication for failures 7 – 9 from the power system.

Beep Codes
Number

Definition

1, 2, 3 beeps

The firmware in flash ROM is corrupt.

4 beeps

The header in the ROM is not valid.

6 beeps

A checksum error occurred after the ROM image was copied into
memory.

2-2

AlphaServer DS20 Service Manual

If the system does not power up
•

Are the power cords plugged in?

•

Is the power supply functioning? (The power supply will shut down if it detects
any faults. See Section 1.11.)

•

Are the cover and side panels closed and the interlock engaged?

If the system comes up and approximately 30 seconds later goes down,
possible failures are:
•

CPU fan failure

•

System fan failure

•

Overtemperature condition

If you hear a series of beeps (1, followed by 2, followed by 3)
These beeps indicate that the firmware in flash ROM is corrupt. The machine hangs
and the floppy light goes on.
Action:
1.

On a working machine, insert the Alpha Systems Firmware Update Version V5.4
(minimum rev.) CD in the CD-ROM drive and copy the file PC264SRM.ROM
found in the DS20 subdirectory onto a floppy renaming the file to
DP264SRM.ROM.

Insert the floppy you just made into the floppy drive on the broken system.

Using the On/Off button, turn the machine off and then back on. The SRM
console will load from the floppy.

Place the Alpha Systems Firmware Update CD in the CD-ROM drive.

Run LFU and update the firmware.

Refer to Appendix C for instructions on updating firmware.
If you hear four beeps
The header in the ROM is not valid, and the system will not boot. Replace the system
board.
If you hear six beeps
Six beeps indicate a checksum error occurred after the ROM image was copied into
memory. Either memory is misconfigured or a memory DIMM needs to be reseated.

Troubleshooting

2-3

2.2

Control Panel Display and Troubleshooting

The control panel display indicates the likely device when testing fails.

Figure 2-1 Control Panel and LCD Display

AlphaServer DS20

PK1408

•

When the On/Off button LED is on, power is applied and the system is running.
When it is off, the system is not running, but power may or may not be present. If
the power supplies are receiving AC power, Vaux is present on the server feature
module regardless of the condition of the On/Off switch.

•

When the Halt button LED is lit and the On/Off button LED is on, the system
should be running either the SRM console or Windows NT.

2-4

AlphaServer DS20 Service Manual

Table 2-1 Control Panel Display
Content of Display

Progress Indicated in Power-Up Flow

Compaq

CPU functioning, path to the OCP operating. Hardware
involved – CPU, C-chip, P-chip 0, PCI to ISA bridge,
ISA to XBUS bridge, OCP controller.

Compaq *

B-cache initialized and both B-cache and memory is
being tested. Additional hardware involved: Backup
cache on the CPU module, D-chips, memory DIMMs.

Compaq Firmware

Firmware loading. Additional hardware involved – TIG
bus.

Compaq Error 06

Memory error. No memory was found, or memory is
bad, or misconfigured, or needs re-seating.

Probe I/O Subsystem

SRM console probing the system. Additional hardware
involved – P-chip 1, all devices on both PCIs.

AlphaServer DS20

Either the SRM console or AlphaBIOS are up and
running.

Troubleshooting

2-5

2.3

Power-Up Display and Troubleshooting

If the power-up display appears, the following hardware is at least partially
functioning: at least one CPU, the C-chip, some D-chips, the P-chips, the TIG
2
bus, the ISA bridge, and the I C bus. The entire power-up display prints to a
serial terminal (if the console environment variable is set to serial); the last
several lines print to either a serial terminal or a graphics monitor. Power-up
status also is seen on the control panel display.

Example 2–1 Power-Up Display
512 Meg of system memory
➊
probing hose 1, PCI
➋
bus 0, slot 7 -- pka -- QLogic ISP1040
bus 0, slot 8 -- ewa -- DECchip 21140-AA
probing hose 0, PCI
probing PCI-to-ISA bridge, bus 1
bus 0, slot 5, function 1 -- dqa -- Cypress 82C693 IDE
bus 0, slot 5, function 2 -- dqb -- Cypress 82C693 IDE
bus 0, slot 6, function 0 -- pkb -- Adaptec AIC-7895
bus 0, slot 6, function 1 -- pkc -- Adaptec AIC-7895
bus 0, slot 7 -- vga -- DEC PowerStorm
bus 0, slot 8 -- ewa -- DECchip 21040-AA
➌
Testing the System
Testing the Disks (read only)
Testing the Network
System Temperature is 22 degrees C
Compaq AlphaServer DS20 Console V5.4, Aug 26 1998 16:07:57 ➍

P00>>>

2-6

AlphaServer DS20 Service Manual

By the time the power-up display is completed,
1. the CPUs have run their self-tests,
2. the SROM has completed its preliminary tests and loaded the SRM console from
flash ROM on the TIG bus into memory,
3. the SROM has passed control to the SRM console,
4. the SRM has polled the system, run its system diagnostics, and has sent the
display characters.
If the system’s operating system is NT, you will not see any of the power-up display
before the line that says “Testing the System.”

➊
➋
➌
➍

Memory size is determined by the C-chip.
The PCI bridges and attendant buses (indicated as IODn by the console) are
probed and the devices are reported. I/O adapters are configured. At a
minimum, the devices are responding to probes by the console program.
The system, disks, and network are tested by the console.
The SRM console banner and prompt are printed. (The SRM prompt is shown in
this manual as P00>>>. It can, however, be P01>>>. The number indicates the
primary processor.) If the auto_action environment variable is set to boot or
restart and the os_type environment variable is set to unix or openvms, the
Compaq Tru64 UNIX or OpenVMS operating system boots.
If the system is running the Windows NT operating system (the os_type
environment variable is set to nt), the SRM console loads and starts the
AlphaBIOS console.
Refer to Chapters 4 and 5 of the AlphaServer DS20 User’s Guide for
information about the SRM console and AlphaBIOS.

Troubleshooting

2-7

2.4

Running Diagnostics — Test Command

The test command runs diagnostics on the entire system, CPU devices, memory
devices, and the PCI I/O subsystem. The test command runs only from the SRM
console. Ctrl/C stops the test. The console cannot be secure.

Example 2–2 Test Command Syntax
P00>>> help test
NAME
test
FUNCTION
Test the system.
SYNOPSIS
test [-lb] [-t <time>]
COMMAND ARGUMENT(S):
P00>>>
P00>>>
P00>>>
SYNOPSIS
test ([-lb] [-t <time>]
The entire system is tested by default.

NOTE: If you are running the Microsoft Windows NT operating system, switch from
AlphaBIOS to the SRM console in order to enter the test command. From the
AlphaBIOS console, press in the Halt button (the LED will light) and reset the system,
or select Tru64 UNIX (SRM) or OpenVMS (SRM) from the Advanced CMOS Setup
screen and reset the system.
test [-lb] [-t time]
-lb

Loop back test enable. Loop back connectors are needed on COM1,
COM2, and the parallel port.

-t time

Specifies the run time in seconds. The default for system test is 600
seconds (10 minutes).

2-8

AlphaServer DS20 Service Manual

2.5

Testing an Entire System

A test command runs all exercisers for subsystems and devices on the system.
I/O devices tested are supported boot devices. The test runs for 2 minutes.

Example 2–3 Sample Test Command
P00>>> test
System test, runtime 120 seconds
Type ^C if you wish to abort testing once it has started
Default zone extended at the expense of memzone.
Use INIT before booting
Testing Ethernet device(s)
Testing VGA
Testing Memory
Testing SCSI disks (read-only)
Testing other SCSI devices (read-only)..
Testing floppy drive (dva0, read-only)
No diskette present, skipping floppy test
ID
Program
Device
Pass Hard/Soft Bytes Wrtn
-------- ------------ ---------- ----- -------- ---------00001c12
memtest memory
1
0
0
352321536
00001c17
memtest memory
1
0
0
352321536
00001c35
memtest memory
1
0
0
352321536
00001c80
exer_kid dkb100.1.0.9
0
0
0
0
00001c83
exer_kid dkb200.2.0.9
0
0
0
0
00001c85
exer_kid dkb300.3.0.9
0
0
0
0
00001cc7
exer_kid dke0.0.0.200
0
0
0
0
00001cc8
exer_kid dke200.2.0.2
0
0
0
0
00001cc9
exer_kid dke400.4.0.2
0
0
0
0
00001cf7
exer_kid dkf100.1.0.2
0
0
0
0
00001cfa
exer_kid dkf300.3.0.2
0
0
0
0

Bytes Rd
---------352321536
352321536
352321536
4915200
4898816
4898816
6144000
6144000
6127616
8830976
8814592

ID
Program
Device
Pass Hard/Soft Bytes Wrtn
-------- ------------ ---------- ---- ---------- ---------00001c12
memtest memory
1
0
0
713031680
00001c17
memtest memory
1
0
0
721420288
00001c35
memtest memory
1
0
0
713031680
00001c80
exer_kid dkb100.1.0.9
0
0
0
0
00001c83
exer_kid dkb200.2.0.9
0
0
0
0
00001c85
exer_kid dkb300.3.0.9
0
0
0
0
00001cc7
exer_kid dke0.0.0.200
0
0
0
0
00001cc8
exer_kid dke200.2.0.2
0
0
0
0
00001cc9
exer_kid dke400.4.0.2
0
0
0
0
00001cf7
exer_kid dkf100.1.0.2
0
0
0
0
00001cfa
exer_kid dkf300.3.0.2
0
0
0
0

Bytes Rd
--------713031680
721420288
713031680
12730368
12713984
12713984
8749056
8749056
8749056
13533184
13516800

Continued on next page
Troubleshooting

2-9

ID
Program
Device
Pass Hard/Soft Bytes Wrtn
Bytes Rd
-------- ------------ ---------- ----- -------- ------------------00001c12
memtest memory
2
0
0
1082130432
1082130432
00001c17
memtest memory
2
0
0
1082130432
1082130432
00001c35
memtest memory
2
0
0
1073741824
1073741824
00001c80
exer_kid dkb100.1.0.9 0
0
0
0
20086784
00001c83
exer_kid dkb200.2.0.9 0
0
0
0
20086784
00001c85
exer_kid dkb300.3.0.9 0
0
0
0
20086784
00001cc7
exer_kid dke0.0.0.200 0
0
0
0
16531456
00001cc8
exer_kid dke200.2.0.2 0
0
0
0
16515072
00001cc9
exer_kid dke400.4.0.2 0
0
0
0
16515072
00001cf7
exer_kid dkf100.1.0.2 0
0
0
0
23511040
00001cfa
exer_kid dkf300.3.0.2 0
0
0
0
23494656
ID
Program
Device
Pass Hard/Soft Bytes Wrtn
-------- ------------ ---------- ----- -------- ---------00001c12
memtest memory
2
0
0
1442840576
00001c17
memtest memory
2
0
0
1442840576
00001c35
memtest memory
2
0
0
1442840576
00001c80
exer_kid dkb100.1.0.9 0
0
0
0
00001c83
exer_kid dkb200.2.0.9 0
0
0
0
00001c85
exer_kid dkb300.3.0.9 0
0
0
0
00001cc7
exer_kid dke0.0.0.200 0
0
0
0
00001cc8
exer_kid dke200.2.0.2 0
0
0
0
00001cc9
exer_kid dke400.4.0.2 0
0
0
0
00001cf7
exer_kid dkf100.1.0.2 0
0
0
0
00001cfa
exer_kid dkf300.3.0.2 0
0
0
0

Bytes Rd
---------1442840576
1442840576
1442840576
28852224
28852224
28852224
19513344
19513344
19513344
29917184
29900800

ID
Program
Device
Pass Hard/Soft Bytes Wrtn
-------- ------------ ---------- ----- -------- ---------00001c12
memtest memory
2
0
0
1803550720
00001c17
memtest memory
2
0
0
1811939328
00001c35
memtest memory
2
0
0
1803550720
00001c80
exer_kid dkb100.1.0.9 0
0
0
0
00001c83
exer_kid dkb200.2.0.9 0
0
0
0
00001c85
exer_kid dkb300.3.0.9 0
0
0
0
00001cc7
exer_kid dke0.0.0.200 0
0
0
0
00001cc8
exer_kid dke200.2.0.2 0
0
0
0
00001cc9
exer_kid dke400.4.0.2 0
0
0
0
00001cf7
exer_kid dkf100.1.0.2 0
0
0
0
00001cfa
exer_kid dkf300.3.0.2 0
0
0
0
^C
P00>>>

Bytes Rd
---------1803550720
1811939328
1803550720
36241408
36241408
36241408
26968064
26968064
26968064
38158336
38158336

2-10

AlphaServer DS20 Service Manual

2.6

Other Useful Console Commands

Several console commands can be used to diagnose the system.

The show power command identifies power, temperature, and fan faults.

Example 2–4

Show Power

P00>>> show power
Power Supply 0
Power Supply 1/Fan Tray
System Fans
CPU Fans
Temperature

Status
good
good
good
good
good

Current ambient temperature is 27 degrees C
System shutdown temperature is set to 55 degrees C
1 Environmental events are logged in nvram
Do you want to view the events? (Y/<N>) y
Total Environmental Events: 1 (1 logged)
1

NOV 11 18:00

System Fan 0 Failure, Power Supply 0,1 Failure

Do you want to clear all events from nvram? (Y/<N>) n
P00>>>

The show memory command shows memory DIMMs and their starting addresses.

Example 2–5 Show Memory
P00>>> show memory
Array #

Size

Base Addr

-------

----------

---------

512 MB

000000000

512 MB

020000000

2
3

256 MB
128 MB

040000000
050000000

Total Bad Pages = 0
Total Good Memory = 1408 MBytes
P00>>>

Troubleshooting

2-11

2.7

Troubleshooting with LEDs

During power-up, reset, initialization, or testing, diagnostics are run on CPUs,
memories, P-chips, and the PCI backplane and its embedded options. Although
system LEDs are not visible when the side panels are on, they can be viewed when
the card cage side of the system is exposed and the top cover is on. There are
LEDs on the CPU and server feature modules.

Figure 2-2 CPU and Server Feature Module LEDs
CPU Self-test
CPU DC OK
SROM Clk
2V OK

CPU
Module

5V OK

Server
Feature
Module

5 Vaux
Power OK

Sys Fan OK
CPU Fan OK
Temp OK

PK1407-99

2-12

AlphaServer DS20 Service Manual

To see LEDs, the card cage side of the system must be exposed; the system top should
be on, and the system must be on.
CPU LEDs
The CPU LEDs are on the under side of the module. Figure 2-2 shows the location of
the LEDs when looking up at the module. Normally all CPU LEDs are on except the
SROM Clock LED.
Replace the CPU if the 5V OK LED is on and any of the following LEDs are off: CPU
DC OK, or 2V OK.
If the 5V OK LED is off, power is not getting to the CPU. The problem could be the
power harness, the power translation board, the power supply, or the CPU.
If the CPU self-test LED is off, the built-in self-test on the CPU chip did not complete
for some reason.
Server Feature Module LEDs
All the LEDs on this module are normally on.
If the 5 Vaux Power OK LED is off, power is not getting to the module and the
problem could be the power harness, the power translation board, the power supply, or
the server feature module.
If the Sys Fan OK LED is off, a system fan is broken. Use the show power command
to determine which.
If the CPU Fan OK LED is off, a CPU fan is broken. Use the show power command
to determine which.
If the Temp OK LED is off, the temperature in the cabinet is above the temperature
threshold. Several things can cause this condition: blocked airflow, temperature in the
room where the system is located is too high, the system card cage is open and air is
not channeled properly over the system. Fix any of these conditions, if possible. The
overtemperature threshold is programmable and is controlled by the environment
variable over_temp. Its default is 55 degrees C. After the system has cooled down
and can be powered up, you can change the threshold. If you do this and the
temperature inside the system gets too hot, it is likely that system errors will occur and
the system may crash. If the system gets too hot, hardware can be damaged.

Troubleshooting

2-13

2.8

Compaq Analyze

Compaq Analyze is the error analysis tool used to analyze errors. An example of
its output is shown here. For information on installing, running, and learning
about Compaq Analyze, go to http://www.evnrud.cxo.dec.com/desta/kits.htm.

2.8.1 Compaq Analyze Graphics Interface (GUI)
Compaq Analyze automatically runs on each of the supported operating systems
on the DS20 system.

Figure 2-3 Compaq Analyze Graphics Interface

PK1411-99

2-14

AlphaServer DS20 Service Manual

Figure 2-3 shows an example of what you can expect to see on a system’s console,
assuming it is a graphics terminal and Compaq Analyze is installed and running in the
backround. When an error is detected, it is reported to the console with a series of
problem found statements. In this case, “an uncorrectable system fan 0 error
detected,” was logged a couple of times in the event log with a time stamp of Friday
March 12, 1999.
To get a full analysis of the error, double click on the Problem Found: hot spot on the
active screen and a full report of the error is displayed.

Troubleshooting

2-15

2.8.2 Description of the Error
After “double clicking” the Problem Found: hot spot on the Compaq Analyze
screen a full description of the error is displayed and a FRU and its location is
called out. Example 2–6 shows a Compaq Analyze error report.

Example 2–6 Compaq Analyze Error Report
Problem Found: An uncorrectable system fan 0 error detected.
Managed Entity:

System Entity: enugu Error Environment:
Record Number :
Event ID_Count:2Event ID_Prefix:15008
Event Time:
Time of Error : Thu, 11 Mar 1999 12:43:58 –0500
Brief Description:

An uncorrectable system fan 0 error detected.
Callout ID:

0020050000072E05
Severity:

2
Reporting Node:

enugu
Full Description:

An uncorrectable system fan 0 error has been diagnosed. This System
error requires replacement service to be administered to Fan 0 Field
Replaceable Unit (FRU). This FRU is physically located in the
compartment to the right of the system card cage and is System Fan 0
– Upper Fan.
FRU List:

Probability: High
Manufacturer: Compaq
Device Type: Power, Cooling, and Temperature
Physical Location: Slot System Fan 0 -FRU Part Number: System fan 0 pn from config tree
FRU Serial Number: Fru SN from config tree
FRU Firmware Rev: NA

2-16

AlphaServer DS20 Service Manual

Evidence:

Entry Errlog: SMM_1838 SysType_34 OS_Type_1 Entry_Type_682
Entry_Type_Ana Mchk_Error_Cod
Event_Header_Common_Fields_V2_0
Event_Leader: xFFFFFFFE
Header_Length: 176
Event_Length: 312
Header_Rev_Major: 2
Header_Rev_Minor: 0
OS_Type: 1
! 1 = UNIX, 2 = OVMS, 3 = NT
Hardware_Arch: 4
CEH_Vendor_ID: 3564
Hdwr_Sys_Type: 34
Logging_CPU: 0
CPUs_In_Active_Set: 2
Major_Class: 115
Minor_Class: 2
DSR_Msg_Num: 1838
! Compaq AlphaServer DS20
CEH_Device: 35
Chip_Type: 8
! 8 = EV6
CEH_Device_ID_0: x0000FFFF
CEH_Device_ID_1: x00000000
CEH_Device_ID_2: x00000000
Unique_ID_Count: 2
Unique_ID_Prefix: 15008
Num_Strings: 2
Event_Header_UNIX_WNT_Specific_Fields_V2_0
Priority: 3
DID_Fmt: x00
Subid_Errcode: xFFFFFFFF
Subid_Num: 0
TLV_Processing_Support
TLV_Time_as_Local: Thu, 11 Mar 1999 12:43:58 -0500
TLV_Computer_Name: enugu
SMM_Decode_Support
System_Marketing_Model: 1838
! Compaq AlphaServer DS20
System_Type: 34
Chip_Type: 8
Member_ID: 6
Chip_Speed: 500
Number_of_CPUs: 1
Entry_Type_Support
Entry_Type: 682
! Machine Check type 682 (environment error)

Continued on next page

Troubleshooting

2-17

Systype34_Env_Regs_V1
Frame_Flags: x00000000
Mchk_Error_Code: x00000206
Frame_Rev: 1
SW_Sum_Flags: x0000000000000000
Cchip_DIR: x0001000000000000
Environ_QW_1: x0000000000000009
Environ_QW_2: x000000000000004F
Environ_QW_3: x0000000000000000
Environ_QW_4: x0000000000000000
Environ_QW_5: x0000000000000000
Environ_QW_6: x0000000000000000
Environ_QW_7: x0000000000000000
Environ_QW_8: x0000000000000000
Environ_QW_9: x0000000000000000
Subpacket_Support
Subpacket_Header_Support
Trailer_Frame_Support
Compaq Analyze Problem Report

2-18

AlphaServer DS20 Service Manual

Of particular interest in the error report is the Full Description of the error. If
Compaq Analyze is able to determine what failed on the machine, it gives a full
description of the failing FRU and its location. In this case the upper system fan is
identified as the failing part and its location is given.
Evidence provided depends upon the type of error detected. The types of errors
detected are given in Table 2-2. The evidence section of the Compaq Analyze report
provides information that lead the tool to identify the failing FRU and its location. For
more information, see the Regatta Platform Fault Management Specification.

Table 2-2 Types of Errors
Error Event

Description

MCHK 670

Processor Machine checks. These are synchronous errors that
inform precisely what happened at the time the error occurred.
They are detected inside the CPU chip and are fatal errors.
System machine checks. These are asynchronous errors that are
recorded after the error has occurred. Data on exactly what was
going on in the machine at the time of the error may not be
known. They are fatal errors.
Processor correctable errors.
System correctable errors.
System environment failures that require repair (power supply
failure, system fan failure, overtemperature condition).
Redundant power supply failure.

MCHK 660

MCHK 630
MCHK 620
MCHK 682 - 685
MCHK 687

Troubleshooting

2-19

2.9

Releasing Secure Mode

The console cannot be secure for most SRM console commands to run. If the
console is not secure, user mode console commands can be entered. See the
system manager if the system is secure and you do not know the password.

Example 2–7

Releasing/Reestablishing Secure Mode

P00>>> login
Please enter password: xxxx
P00>>>
[User mode SRM console commands are now available.]
P00>>> set secure
The console command login clears secure.
If the password has been forgotten and the system is in secure mode, enter the login
command:
P00>>> login
please enter password:
At this prompt, press the Halt button and then press the Return key.
The password is now cleared and the console is in user mode. A new password must
be set to put the console into secure mode again.
For a full discussion of securing the console, see your system User’s Guide.

2-20

AlphaServer DS20 Service Manual

Chapter 3
Error Registers
This chapter describes the following registers used to hold error information:
•

Ibox Status Register - I_STAT

•

Memory Management Status Register – MM_STAT

•

Dcache Status Register – DC_STAT

•

Cbox Read Register

•

Miscellaneous Register (MISC)

•

Device Interrupt Request Register (DIRn, n=0,1)

•

Pchip Error Register (PERROR)

•

Failure Register

•

Function Register

Error Registers 3-1

3.1

Ibox Status Register - I_STAT

The Ibox Status Register (I_STAT) is a read/write-1-to-clear register that
contains Ibox status information. The register is read only by PAL code and is
an element in the CPU or System Uncorrectable Machine Check Error Logout
frame.

31 30 29 28

TPE
DPE

PK1414-99

Table 3-1 Ibox Status Register
Name

Bits

Type

Description

Reserved

<63:31>

Reserved for Compaq.

DPE

<30>

W1C

Icache data parity error
When set, indicates that the Icache
encountered a data parity error on instruction
fetch.

TPE

<29>

W1C

Icache tag parity error
When set, indicates that the Icache
encountered a tag parity error on instruction
fetch.

Reserved

<28:0>

Reserved for Compaq.

3-2 AlphaServer DS20 Service Manual

3.2

Memory Management Status Register –
MM_STAT

The Memory Management Status Register (MM_STAT) is a read-only register.
When a Dstream TB miss or fault occurs, information about the error is latched
in MM_STAT. This register is not updated when a LD_VPTE gets a DTB miss
instruction. The register is read only by PALcode and is an element in the CPU
or System Uncorrectable Machine Check Error Logout frame.

11 10 9

4 3 2 1 0

DC_TAG_PERR
OPCODES<5:0>
FOW
FOR
ACV
WR
PK1415-99

Error Registers 3-3

Table 3-2 Memory Management Status Register
Name

Bits

Reserved

<63:11>

Type

Description
Reserved for Compaq.

DC_TAG <10>
_PERR

This bit is set when a Dcache tag parity error occurs
during the initial tag probe of a load or store
instruction. The error created a synchronous fault
to the D_FAULT PALcode entry point and is
correctable. The virtual address associated with the
error is available in the VA register.

OPCODE <9:4>

Opcode of the instruction that caused the error.
HW_LD is displayed as 3 and HW_ST is displayed
as 7.

FOW

<3>

Set when a fault-on-write error occurs during a
write transaction and PTE[FOW] was set.

FOR

<2>

Set when a fault-on-read error occurs during a read
transaction and PTE[FOR] was set.

ACV

<1>

Set when an access violation occurs during a
transaction. Access violations include a bad virtual
address.

<0>

Set when an error occurs during a write transaction.

3-4 AlphaServer DS20 Service Manual

3.3

Dcache Status Register – DC_STAT

The Dcache Status Register (DC_STAT) is a read-write register. If a Dcache tag
parity error or data ECC error occurs, information about the error is latched in
this register. The register is read only by PALcode and is an element in the CPU
or System Uncorrectable Machine Check Error Logout frame.

4 3 2 1 0

SEO
ECC_ERR_LD
ECC_ERR_ST
TPERR_P1
TPERR_P0

PK1416-99

Error Registers 3-5

Table 3-3 Dcache Status Register
Name

Bits

Type

Description

Reserved

<63:5>

SEO

<4>

W1C

Second error occured. When set, indicates that a
second Dcache store ECC error occurred within 6
cycles of the previous Dcache store ECC error.

ECC_ERR <3>
_LD

W1C

ECC error on load. When set, indicates that a
single-bit ECC error occurred while processing a
load from the Dcache or any fill.

ECC_ERR <2>
_ST

W1C

ECC error on store. When set, indicates that an
ECC error occurred while processing a store.

TPERR_P1 <1>

W1C

Tag parity error — pipe 1. When set, indicates that
a Dcache tag probe from pipe 1 resulted in a tag
parity error. The error is uncorrectable and results
in a machine check.

TPERR_P0 <0>

W1C

Tag parity error — pipe 0. When set, this bit
indicates that a Dcache tag probe from pipe 1
resulted in a tag parity error. The error is
uncorrectable and results in a machine check.

Reserved for Compaq.

3-6 AlphaServer DS20 Service Manual

3.4

Cbox Read Register

The Cbox Read Register is read 6 bits at a time. Table 3-4 shows the ordering
from LSB to MSB. The register is read only by PALcode and is an element in the
CPU or System Uncorrectable Machine Check Error Logout frame.

Table 3-4 Cbox Read Register
Name

Description

C_SYNDROME_1
<7:0>

Syndrome for the upper QW in the OW of victim that was
scrubbed.

C_SYNDROME_0
<7:0>

Syndrome for the lower QW in the OW of victim that was
scrubbed.

C_STAT<4:0>

Bits

Error status

00000

Either no error, or error on a speculative load, of a
Bcache victim read due to a Dcache/Bcache miss.

00001

BC_PERR (Bcache tag parity error)

00010

DC_PERR (duplicate tag parity error

00011

DSTREAM_MEM_ERR

00100

DSTREAM_BC_ERR

00101

DSTREAM_DC_ERR

0011X

PROBE_BC_ERR

01000

Reserved

01001

Reserved

01010

Reserved

01011

ISTREAM_MEM_ERR

01100

ISTREAM_BC_ERR

01101

Reserved

1XXXX

DOUBLE_BIT_ERROR

Error Registers 3-7

Table 3-4 Cbox Read Register (Continued)
Name

Description

C_STAT<3:0>

If C_STAT equals xxx_MEM_ERR or xxx_BC_ERR, then
C_STAT contains the status of the block as follows; otherwise, the
value of C_STAT is X.
Bit valus

C_ADDR
<6:42>

Status of block

7- 4

Reserved

Parity

Valid

Dirty

Shared

Address of the last reported ECC or parity error. If C_STAT value
is DSTREAM_DC_ERR, only bits <6:19> are valid.

3-8 AlphaServer DS20 Service Manual

3.5

Miscellaneous Register (MISC)

This register is designed so that only writes of 1 affect it. When a 1 is written to
any bit in the register, the programmer does not need to be concerned with readmodify-write or the status of any other bits in the register. Once NXM is set, the
NXS field is locked. It is unlocked when software clears the NXM field. The
ABW (arbitration won) field is locked if either ABW bit is set, so the first CPU to
write it locks out the other CPU. Writing a 1 to ACL (arbitration clear) clears
both ABW bits and both ABT (arbitration try) bits and unlocks the ABW field.

Address

801 A000 0040

Access

44 43

40 39

reserved
DEVSUP
REV

29 28 27

25 24 23

000

20 19

16 15

4 3 2 1 0

NXM
NXS
ACL
ABT
ABW
IPREQ
IPINTR
ITINTR
CPUID
PK1417-99

Error Registers 3-9

Table 3-5 Miscellaneous Register
Name

Bits

Type

Initial
State Description

RES

<63:44>

MBZ, RAZ

DEVSUP

<43:40>

REV

<39:32>

Latest revision of the Cchip:
1 = Tsunami

NXS

<31:29>

NXM source – Device that
caused the NXM.
Unpredictable if NXM not set.
0 = CPU0, 1 = CPU1.

NXM

<28>

R, W1C

Nonexistent memory address
detected. Sets DRIR<63> and
locks the NXS field until it is
cleared.

RES

<27:25>

MBZ, RAZ

Reserved.

ACL

<24>

Arbitration clear – writing a 1
to this bit clears the ABT and
ABW fields.

ABT

<23:20>

R, W1S

Arbitration try – writing a 1 to
these bits sets them.

ABW

<19:16>

R, W1S

Arbitration won – writing a 1
to these bits sets them unless
one is already set, in which
case the write is ignored.

IPREQ

<15:12>

Interprocessor interrupt
request – write a 1 to the bit
corresponding to the CPU you
want to interrupt. Writing a 1
here sets the corresponding bit
in the IPINTR.

IPINTR

<11:8>

R, W1C

Interprocessor interrupt
pending – one bit per CPU.
Pin irq<3> is asserted to the
CPU corresponding to a 1 in
this field.

3-10 AlphaServer DS20 Service Manual

Reserved.

Table 3-5 Miscellaneous Register (Continued)
Name

Bits

Type

Initial
State Description

ITINTR

<7:4>

R, W1C

Interval timer interrupt
pending – one bit per CPU.
Pin irq<2> is asserted to the
CPU corresponding to a 1 in
this field.

RES

<3:2>

MBZ, RAZ

Reserved.

CPUID

<1:0>

ID of the CPU performing the
read.

Error Registers 3-11

3.6

Device Interrupt Request Register (DIRn, n=0,1)

These registers indicate which interrupts are pending to the CPUs and indicate
the presence of an I/O error condition.

Address

801 A000 0280 CPU0
801 A000 02C0CPU1

Access

58 57 56 55

IRQ1 PCI interrupts pending
Reserved
ERR

IRQ1 PCI interrupts pending
PK1418-99

Table 3-6 Device Interrupt Request Register
Name

Bits

Type

Initial
State Description

ERR

<63:62>

IRQ0 error interrupts
<63> Cchip detected MISC <NXM>
<62> Pchip0 error
<62> Pchip1 error

RES

<61:56>

Reserved

NXS

<55:0>

IRQ1 PCI interrupts pending to the CPU

3-12 AlphaServer DS20 Service Manual

3.7

Pchip Error Register (PERROR)

If any bits <11:0> are set, this register is frozen. Only bit <0> can be set after
that. All other values are held until all bits <11:0> are clear. When an error
occurs and one of the <11:0> bits set, the associated information is captured in bit
<63:16>. After the information is captured, the INV bit is cleared, but the
information is not valid and should not be used if INV is set.

Address

801 8000 03C0 P0 ERROR
803 8000 03C0 P1 ERROR

Access

56 55

52 51 50

44 43

40 39

ADDR
INV
CMD
SYN

16 15

12 11 10 9 8 7 6 5 4 3 2 1

ADDR
RES
CRE
UECC
RES
NDS
RDPE
TA
APE
SGE
DCRTO
PERR
SERR
LOST
PK1419-99

Error Registers 3-13

Table 3-7 Pchip Error Register
Name

Bits

Type

Initial
State Description

SYN

<63:56>

ECC syndrome of error if CRE or
UECC.

CMD

<55:52>

PCI command when error occurred if not
CRE or UECC.
If CRE or UECC, then:
Value

Command

0000

DMA read

0001

DMA read-modify-write

0011

SGTE read

Others

Reserved

INV

<51>

RO Rev1
RAZ Rv0

Info Not Valid – meaningful when one
of bits <11:0> is set. Indicates the
validity of SYN, CMD, and ADDR bits.
Valid = 0, Invalid = 1.

ADDR

<50:16>

If CRE or UECC, then ADDR<50:19> =
system address <34:3> of erroneous
quadword and ADDR<18:16> = 0.
If not CRE and not UECC, then
ADDR<50:48> = 0;
ADDR<47:18> = starting PCI address
<31:2> of transaction when error was
detected;
ADDR<17:16> = 00 → not a DAC
operation;
ADDR<17:16> = 01 → via DAC SG
Window 3;
ADDR<17> = 1 → via Monster Window

RES

<15:12>

MBZ, RAZ 0

Reserved

CRE

<11>

R, W1C

Correctable ECC error.

UECC

<10>

R, W1C

Uncorrectable ECC error.

RES

<9>

MBZ, RAZ 0

Reserved.

NDS

<8>

R, W1C

No b_devsel_l as PCI master.

3-14 AlphaServer DS20 Service Manual

Table 3-7 Pchip Error Register (Continued)

Name

Bits

Type

Initial
State Description

RDPE

<7>

R,W1C

PCI read data parity error as PCI master.

<6>

R, W1C

Target abort as PCI master.

APE

<5>

R, W1C

Address parity error detected as potential PCI
target.

SGE

<4>

R, W1C

Scatter-gather had invalid page table entry.

DCRTO

<3>

R, W1C

Delayed completion retry timeout as PCI
target.

PERR

<2>

R, W1C

b_perr_l sampled asserted.

SERR

<1>

R, W1C

b_serr_l sampled asserted.

LOST

<0>

R, W1C

Lost an error because it was detected after
this register was frozen, or while in the
process of clearing this register.

Error Registers 3-15

3.8

Failure Register
2

This register, on the I C bus, is locked when there is a power supply or fan
failure. Together with the Function Register, fan and power supply failures are
identified and reported to the operating system thus notifying it that the system
will shut down in 30 seconds. The results of reading this register are displayed by
the SRM show power console command.

I C Bus Address

0111000

Access

Read Only

Reserved
C/SFAN0_L
Reserved
Reserved
PS1_PRESENT_L/FAN TRAY
C/SFAN1_L
Reserved
PS0_PRESENT_L
PK1420-99

3-16 AlphaServer DS20 Service Manual

Table 3-8 Failure Register
Name

Bits

Initial
Type State Description

PS0_PRESENT_L <7>

If the bit is clear, power supply 0 is
present.

Reserved

<6>

Reserved

C/SFAN1_L

<5>

When set, indicates that either the
system fan 1 or the fan on the
heatsink on CPU1 failed. Which
failed is determined by the state of
SYSFAN_OK and CPUFANS_OK
in the Function Register.

PS1_PRESENT_L <4>
/FAN TRAY

If the bit is clear, either power
supply 1 or the system fan tray is
present.

Reserved

<3>

Reserved

<2>

Reserved

C/SFAN0_L

<1>

When set, indicates that either the
system fan 0 or the fan on the
heatsink on CPU0 failed. Which
failed is determined by the state of
SYSFAN_OK and CPUFANS_OK
in the Function Register.

Reserved

<0>

Reserved

Error Registers 3-17

3.9

Function Register
2

The Function Register generates an interrupt on the I C bus if one of the critical
functions monitored (power, temperature, fan operation) goes beyond
predetermined limits. When such an interrupt is generated, the contents of bits
<0, 1, 2, and 5> in the Failure Register are frozen. The system will shut down 30
seconds after the interrupt is posted. The results of reading this register are
displayed by the SRM show power console command.

I2C Bus Address

0111001

Access

0
TEMP_OK
SYSFAN_OK
Reserved
CPUFANS_OK
FANTRAY_FAIL_H
PS0_OK_L
PS1_OK_L
Reserved
PK1421-99

3-18 AlphaServer DS20 Service Manual

Table 3-9 Function Register
Name

Bits

Type

Initial
State Description

Reserved

<7>

Reserved

PS1_OK_L

<6>

When set, indicates that power
supply 1 is functioning properly.

PS0_OK_L

<5>

When set, indicates that power
supply 0 is functioning properly.

FANTRAY_FAIL_H <4>

When clear, indicates that the
fantray, if present is functioning
properly.

CPUFANS_OK

<3>

When set, indicates that the fans on
CPU heatsinks are functioning
properly.

Reserved

<2>

Reserved

SYSFAN_OK

<1>

When set, indicates that the system
fans are functioning properly.

TEMP_OK

<0>

When set, indicates that the
temperature inside the system
enclosure is below the temperature
limit.

Error Registers 3-19

Chapter 4
Removal and Replacement
This chapter describes removal and replacement procedures for field-replaceable units
(FRUs).

4.1

System Safety

Observe the safety guidelines in this section to prevent personal injury.

CAUTION: Wear an antistatic wrist strap whenever you work on a system.
WARNING: When the system is off and plugged into an AC outlet, auxiliary power is
still supplied to the system. To remove all power, unplug the power supply. Note
though that unplugging the system will turn off LEDs that could identify the problem.
When the system interlocks are disabled and the system is still powered on, voltages
are low in the system, but current is high. Observe the following guidelines to prevent
personal injury.
1.
2.

Remove any jewelry that may conduct electricity before working on the system.
If you need to access the system card cage, power down the system and wait 2
minutes to allow components in that area to cool.

Removal and Replacement 4-1

4.2

FRU List

Figure 4-1 shows of the FRU locations and Table 4-1 lists the part numbers of the
field-replaceable units.

Figure 4-1 Some of the FRU Locations
CD-ROM

SCSI
Disks

OCP and
Display

Memory
CPU

CPUs
Auxiliary Fan
or Optional
Power Supply

Floppy
System Fan 0

Memory

Server Feature
Module

Power
Supply

System Fan 1

I/O Options
System Board
PK1497-87

4-2 AlphaServer DS20 Service Manual

Table 4-1 Field-Replaceable Unit Part Numbers
CPU Modules
54-24758-01 C01

500 MHz CPU, 4 Mbyte cache

Memory Modules
54-25066-BA

32 Mbyte DIMM

54-25053-BA

64 Mbyte DIMM

54-25941-KA

128 Mbyte DIMM

54-25941-BA

256 Mbyte DIMM

System Backplane, Display, and Support Hardware
54-25756-01 D02

System board

54-25580-01

Server feature module

RX23L-AC

Floppy

RRD47-AC

CD-ROM

54-23302-02

OCP assembly

70-31349-01

Speaker assembly

Fans
70-31351-01 & -02

Cooling fan 120x120

70-33195-02

Auxiliary cooling fan assembly

Power System Components
30-48043-01

Power supply (cables connect to the power transition
module)

54-25588-01

Power transition module

SCSI Hardware
54-23365-01 & -02

SCSI backplane

30-48985-01

UltraSCSI bus extender

Removal and Replacement 4-3

Table 4-1 Field-Replaceable Unit Part Numbers (Continued)
Power Cords
BN26J-1K

North America, Japan 12V, 75-inches long

BN19H-2E

Australia, New Zealand, 2.5m long

BN19C-2E

Central Europe, 2.5m long

BN19A-2E

UK, Ireland, 2.5m long

BN19E-2E

Switzerland 2.5m long

BN19K-2E

Denmark, 2.5m long

BN19Z-2E

Italy, 2.5m long

BN19S-2E

Egypt, India, South Africa, 2.5m long

BN18L-2E

Israel, 2.5m long

Ultra SCSI Signal Cables

From

17-04890-01

68 pin connector
cable

SCSI controller

UltraSCSI bus
extender

17-04022-03

68 pin connector
cable

UltraSCSI bus
extender

SCSI backplane
signal connector

17-04021-01

68 pin conn jumper

SCSI backplane

17-04795-01

68 pin connector
cable

External port, SCSI
backplane

Terminator

12-41768-03

68 pin terminator

End or 17-04795-01

System Cables and Jumpers

From

17-04532-01

Current share cable

Crrnt shr conn, PS0

Crrnt shr conn, PS1

17-03970-01

34 pin Floppy signal
cable

Flop connector on
system board

Floppy

17-03971-06

OCP signal

OCP connector on
server feature module

OCP signal

Twisted pair (y & g)

RCM connector on
server feature module

Power connector on
OCP

Twisted pair (red
and black)

OCP

Interlock switch
pigtail

4-4 AlphaServer DS20 Service Manual

Table 4-1 Field-Replaceable Unit Part Numbers (Continued)
System Cables and
Jumpers

From

70-31348-01

Interlock switch
and pigtail cable

Interlock
switch
assembly

Twisted pair (red and
black) OCP DC enable
power cable from OCP
connector

17-04796-01

20 pin signal cable

RCM con on
system board

RCM connector on server
feature module

17-04886-01

SCSI CD-ROM
signal cable

SCSI
backplane

CD-ROM signal
connector

17-04735-01

24 pin power
harness

Power supply

Power transition module

70-33578-01

Power harness

Power
transition

3 connectors on sys board,
connector on CPU(s)

Power supply

server feature module
CD-ROM drive power
Floppy power
Optional drive above flop
Single UltraSCSI config
StorageWorks backplane
and power cable to UltraSCSI bus extender
Dual UltraSCSI config
two power cables to two
SCSI bus extenders

Power harness

UltraSCSI bus extender(s)
power and StorageWorks
backplane

17-04700-01

Power cable to
UltraSCSI bus
extender(s) Y
cable(s)

Removal and Replacement 4-5

4.3

System Access

Three sheet metal covers, one on top and one on each side, when removed provide
access to the system card cage and the power/SCSI sections of the system.

Figure 4-2 Accessing the System
Top Cover
Release Latch

4-6 AlphaServer DS20 Service Manual

Exposing the System
CAUTION: Be sure the system On/Off button is in the “off” position before removing
system covers.
1.

Shut down the operating system.

Press the On/Off button to turn the system off.

Unlock and open the door that exposes the storage shelf.

Pull down the top cover latch shown in Figure 4-2 until it latches in the down
position.

Grasp the finger groove at the rear of the top cover and pull it straight back about
2 inches and then lift it off the cabinet.

Pull a side panel back a few inches, tilt the top away from the machine, and lift it
off. (Repeat for the other side.)

From the back, removing the right side cover exposes the system card cage;
removing the left side cover exposes the power supply and SCSI backplane.

Dressing the System
Reverse the steps in the exposure process.

Removal and Replacement 4-7

4.4

CPU Removal and Replacement

CAUTION: Make sure all CPU modules are the same variant.

Figure 4-3 Removing CPU Module

PK1477-98

WARNING: CPU modules and memory modules have parts that operate at high
temperatures. Wait 2 minutes after power is removed before touching any module.

4-8 AlphaServer DS20 Service Manual

Removal
1.

Shut down the operating system and turn the system off.

Expose the card cage side of the system (see Section 4.3).

Detatch the power cable from the CPU.

Loosen the two captive screws holding the module to the card cage.

Pull the CPU module from the system.

Replacement
Reverse the steps in the Removal procedure.
Verification — DIGITAL UNIX and OpenVMS Systems
1.

Bring the system up to the SRM console by pressing the Halt button, if necessary.

Issue the show cpu command to display the status of the new module.

Verification — Windows NT Systems
1.

Start AlphaBIOS Setup, select Display System Configuration, and press Enter.

Using the arrow keys, select Systemboard Configuration to display the status of
the new module.

Removal and Replacement 4-9

4.5 Memory Module Removal and Replacement
CAUTION: Several different memory DIMMs work in these systems. Be sure you are
replacing the broken DIMM with the same variant.

Figure 4-4 Removing Memory

IP00315A

WARNING: CPU modules and memory DIMMs have parts that operate at high
temperatures. Wait 2 minutes after power is removed before touching any module.

4-10 AlphaServer DS20 Service Manual

Removal
1.

Shut down the operating system and turn the system off.

Expose the card cage side of the system (see Section 4.3).

There are levers on the connectors in each memory slot on the system board.
Press both levers in an arc away from the DIMM and gently pull the DIMM from
the connector.

Replacement
Reverse the steps in the Removal procedure.
NOTE: Memory DIMMs are installed in banks of four modules of the same size.
When you replace a DIMM, be sure its size is the same as the one you removed.
Verification — DIGITAL UNIX and OpenVMS Systems
1.

Bring the system up to the SRM console by pressing the Halt button, if necessary.

Issue the show memory command to display the status of the new memory.

Verify the functioning of the new memory by issuing the test command.

Verification — Windows NT Systems
1.

Start AlphaBIOS Setup, select Display System Configuration, and press Enter.

Using the arrow keys, select Memory Configuration to display the status of the
new memory.

Switch to the SRM console (press the Halt button in so that the LED on the button
lights and reset the system). Verify the functioning of the new memory by issuing
the test command.

Removal and Replacement 4-11

4.6

System Board Removal and Replacement

Figure 4-5 Removing System Board

Module
Brace
System Board

PK1498-98

4-12 AlphaServer DS20 Service Manual

Removal
1.

Shut down the operating system and turn the system off.

Unplug the AC power cord. (Auxiliary power is applied to the server feature
module and parts of the system board even when the system is turned off.)

Expose the card cage side of the system (see Section 4.3).

Remove memory.

Remove all CPUs.

Remove all PCI and ISA options.

From the back of the cabinet, using a Phillips head screwdriver, unscrew the four
screws holding the CPU module brace from the system frame. Remove the brace.

Unplug all cables connected to the system board and clear access to all screws
holding the system board in place.

Using a Phillips head screwdriver, unscrew the fifteen screws holding the system
board in place and remove it from the system. Note the two guide studs, one in
the upper right corner and the other in the lower left corner, that protrude through
holes in the system board.

Replacement
Reverse the steps in the Removal procedure.
Verification
Power up the system (press the Halt button if necessary to bring up the SRM console)
and issue the show device command at the console prompt to verify that the system
sees all system options and peripherals.

Removal and Replacement 4-13

4.7

PCI/ISA Option Removal and Replacement

Figure 4-6 Removing PCI/ISA Option

Slot Cover
Screws

Option Card
IP00225

WARNING: To prevent fire, use only modules with current limited outputs. See
National Electrical Code NFPA 70 or Safety of Information Technology Equipment,
Including Electrical Business Equipment EN 60 950.

4-14 AlphaServer DS20 Service Manual

Removal
1.

Shut down the operating system and turn the system off.

Expose the card cage side of the system (see Section 4.3).

To remove the faulty option: Disconnect cables connected to the option. Remove
cables to other options that obstruct the option you are removing. Unscrew the
small Phillips head screw securing the option to the card cage. Slide it from the
system.

Replacement
Reverse the steps in the Removal procedure.
Verification — DIGITAL UNIX and OpenVMS Systems
1.

Power up the system (press the Halt button if necessary to bring up the SRM
console) and run the ECU to restore ISA configuration data.

Issue the show config command or show device command at the console prompt
to verify that the system sees the option you replaced.

Run any diagnostic appropriate for the option you replaced.

Verification — Windows NT Systems
1.

Start AlphaBIOS Setup, select Display System Configuration, and press Enter.

Using the arrow keys, select PCI Configuration or ISA Configuration to
determine that the new option is listed.

Removal and Replacement 4-15

4.8

Server Feature Module Removal and
Replacement

Figure 4-7 Removing Server Feature Module

System
Board

FAN
0

FAN
1

Server Feature
Module

PK1403-98

4-16 AlphaServer DS20 Service Manual

Removal
1.

Shut down the operating system and turn the system off.

Unplug the AC power cords. (Auxiliary power is applied to the server feature
module and parts of the system board even when the system is turned off.)

Expose the card cage section of the system (see Section 4.3).

Unplug all cables connected to the server feature module.

Pinch each plastic snap holding the transition module in place with a pair of
needle-nose pliers and pull the module away from the frame so each snap is
closed and no longer grips the module.

Once all the snaps are released, gently pull the module off the snaps and remove
the module.

Replacement
Reverse the steps in the Removal procedure.
Verification
Power up the system.

Removal and Replacement 4-17

4.9

Power Supply Removal and Replacement

Figure 4-8 Removing Power Supply
4 rear screws
6/32 inch

Power
Supply 1
(Optional)

Power
Supply 0

Internal
screw 3.5 mm
PK1499-98

4-18 AlphaServer DS20 Service Manual

Removal
1.

Shut down the operating system and turn the system off.

Expose the power section of the system (see Section 4.3).

Unplug the AC power cord. (Auxiliary power is applied to the server feature
module and parts of the system board even when the system is turned off.)

Unplug all the cables to the power supply and unplug the power cables to the
transition module.

Remove the four screws at the back of the system cabinet and the single screw at
the back of the power supply that hold the power supply in place.

If you are removing power supply 0, slide the supply out the side of the cabinet.
If you are removing power supply 1, lift the supply out the top of the cabinet.

Replacement
Reverse the steps in the Removal procedure.
Verification
Power up the system.

Removal and Replacement 4-19

4.10 Power Harness Removal and Replacement
Figure 4-9 Removing Power Harness

PK1404-99

4-20 AlphaServer DS20 Service Manual

Removal
1.

Shut down the operating system and power down the system.

Remove the AC power cords. (Auxiliary power is applied to the server feature
module and parts of the system board even when the system is turned off.)

Expose both the card cage section and the power section of the system (see
Section 4.3).

Remove the cable clip between the power section and the card cage section of the
system.

Unplug the cable connection to the server feature module and thread the cable
through from the fan section into the card cage section. Leave the cable loose and
out of the way.

Unplug the cable connections to the CPU(s) and thread them up to the top of the
card cage section above CPU0. Leave the cable loose and out of the way.

Unplug the three cable connections to the system board; two connections on top
right corner of the board and one about 2 inches below the CPU1 slot on the right
of the board. Leave the cable loose and out of the way.

Unplug the cable connection to the floppy and, if applicable, to the optional
device above the floppy. Again leave the cable loose and out of the way.

Remove the power supply (see Section 4.9).

10. Unplug the cable connection to the CD-ROM.
11. Unplug the cable connections to the repeater card(s) and/or the StorageWorks
backplane.
12. Unplug all the connections to the power transition module.
13. As you remove the power harness from the system, be careful as you thread that
piece of the cable that passes from the power section into the card cage section
below the system board.
Replacement
Reverse the steps in the Removal procedure.
Verification
Power up the system.

Removal and Replacement 4-21

4.11 Power Transition Module Removal and
Replacement
Figure 4-10 Removing Power Transition Module

PK1402-98

4-22 AlphaServer DS20 Service Manual

Removal
1.

Shut down the operating system and turn the system off.

Remove the AC power cords.

Expose both the card cage section and the power section of the system (see
Section 4.3).

Remove the power supply(s) (see Section 4.9).

Unplug the fan cable connected to the power transition module.

Fold the power harness up over the top of the system so that it does not interfere
with access to the module.

Pinch each plastic snap holding the transition module in place with a pair of
needle-nose pliers and pull the module away from the frame so each snap is
closed and no longer grips the module.

Once all the snaps are released, gently pull the module off the snaps.

Replacement
Reverse the steps in the Removal procedure.
Verification
Power up the system. If the fan is faulty, the system will run for approximately 30
seconds and then power off.

Removal and Replacement 4-23

4.12 Auxiliary Fan Removal and Replacement
Figure 4-11 Removing Auxiliary Fan

Power Transition
Module

PK1481 - 98

4-24 AlphaServer DS20 Service Manual

Removal
1.

Shut down the operating system and power down the system.

Unplug the AC power cord.

Expose the power section of the system (see Section 4.3).

Unplug all cables connected to the power transition module.

From the rear, remove the four screws holding the auxiliary fan in place.

Remove the fan.

Replacement
Reverse the steps in the Removal procedure.
Verification
Power up the system.

Removal and Replacement 4-25

4.13 System Fan Removal and Replacement
Figure 4-12 Removing System Fan

Module Guides

FAN
0

FAN
1

PK1400-98

4-26 AlphaServer DS20 Service Manual

Removal
1.

Shut down the operating system and turn the system off.

Unplug the AC power cord. (Auxiliary power is applied to the server feature
module and parts of the system board even when the system is turned off.)

Expose the card cage side of the system (see Section 4.3).

Removing Fan 0
4.

Remove the CPU module(s).

Unplug the power cord to fan 0 from the server feature module.

Unscrew the fan from the frame and remove it from the system.

Removing Fan 1
4.

Remove any PCI modules that prevent access to the four Phillips head screws that
hold fan 1 in place.

Remove any plastic module guides that prevent access to the Phillips head screws.

Unplug the power cord to fan 1 from the server feature module.

Unscrew the fan from the frame and remove it from the system.

Replacement
Reverse the steps in the Removal procedure.
Verification
Power up the system. If the fan is faulty, the system will run for approximately 30
seconds and then power down.

Removal and Replacement 4-27

4.14 Cover Interlock Removal and Replacement
Figure 4-13 Removing Cover Interlock
Interlock
Switch

1
PKW0519A-97

4-28 AlphaServer DS20 Service Manual

Removal
1.

Shut down the operating system and turn the system off.

Expose the card cage side of the system (see Section 4.3).

Unplug the AC power cord.

Loosen the screw that holds the CD-ROM bracket to the system (➊ in Figure
4-13).

Detach both the power and the signal connectors at the rear of the CD-ROM.

Pull the CD-ROM and the bracket a short distance toward the rear of the system
and lift them out of the cabinet.

Unplug the interlock switch’s pigtail cable from the cable it is connected to.

Remove the two screws holding the interlock in place and remove the interlock
(➋).

Replacement
Reverse the steps in the Removal procedure.
Verification
Power up the system. If the switch is faulty, the system will not power up.

Removal and Replacement 4-29

4.15 Operator Control Panel Removal and
Replacement
Figure 4-14 Removing OCP

OCP

PKW-0501A-97

4-30 AlphaServer DS20 Service Manual

Removal
1.

Shut down the operating system and turn the system off.

Expose the card cage side of the system (see Section 4.3).

To remove the StorageWorks door:
a.

Open the door slightly and grab the left edge of the door with your left hand
and the right edge of the door with your right hand.

While pushing the door up, bend it by pulling it away from the system. The
door compresses enough so its bottom post slips out of its retaining hole.

Once the bottom of the door is free, gently pull the top down to release it
from the post on the door jam and release it from the spring.

Put the door aside.

Using a Phillips head screwdriver, remove the nine screws holding the molded
plastic front panel to the system. (Six screws are accessed from the front of the
system and three through the fan compartment.)

Tilt the front panel away from the system and disconnect all the cables from the
OCP.

Once the front panel is removed, unscrew the four screws holding the OCP to the
front panel.

Replacement
Reverse the steps in the Removal procedure.
Verification
Power up the system. If the OCP you installed is faulty, the system will not power up.

Removal and Replacement 4-31

4.16 CD-ROM Removal and Replacement
Figure 4-15 Removing CD-ROM

PKW0519-97

4-32 AlphaServer DS20 Service Manual

Removal
1.

Shut down the operating system and turn the system off.

Expose the card cage side of the system (see Section 4.3).

Loosen the two screws holding the CD-ROM to its bracket (see Figure 4-15).

Detach both the power and signal connectors at the rear of the CD-ROM.

Pull the CD-ROM forward out of the system.

Replacement
Reverse the steps in the Removal procedure.
Verification
Power up the system. You can use the SRM test command to test the CD-ROM or, to
save time, use the following SRM console commands:
(Place a CD in the CD-ROM drive.)
P00>>> show dev dkxx
P00>>> HD buf/dka nnn
where nnn is the device number; for example, dka500.

Removal and Replacement 4-33

4.17 Floppy Removal and Replacement
Figure 4-16 Removing Floppy

PK1401-98

4-34 AlphaServer DS20 Service Manual

Removal
1.

Shut down the operating system and turn the system off.

Unplug the AC power cords.

Expose the card cage side of the system (see Section 4.3).

Detatch the power and signal cables from the back of the floppy.

Remove the two Phillips head screws holding the floppy in the system (➊ in
Figure 4-16).

Slide the floppy out the front of the system.

Replacement
Reverse the steps in the Removal procedure.
Verification
Power up the system (press the Halt button if necessary to bring up the SRM console).
You can use the SRM test command to test the floppy or, to save time, use the
following SRM console commands:
(Place a floppy in the drive.)
P00>>> show dev floppy
P00>>> HD buf/dva0

Removal and Replacement 4-35

4.18 SCSI Disk Removal and Replacement
Figure 4-17 Removing StorageWorks Disk

PKW0501B-97

4-36 AlphaServer DS20 Service Manual

Removal
1.

Shut down the operating system and turn the system off.

Open the front door exposing the StorageWorks disks.

Pinch the clips on both sides of the disk and slide it out of the shelf.

Replacement
Reverse the steps in the Removal procedure.
Verification
Power up the system. Use the show device console commands to verify that the
system sees the disk you replaced.

Removal and Replacement 4-37

4.19 StorageWorks Backplane Removal and
Replacement
Figure 4-18 Removing StorageWorks Backplane
StorageWorks
Backplane

UltraSCSI
bus extender
(optional)

UltraSCSI
bus extender

PK1412-99

4-38 AlphaServer DS20 Service Manual

Removal
1.

Shut down the operating system and turn the system off.

Unplug the AC power cords.

Expose the power section of the system (see Section 4.3).

Remove the power and signal cables from the UltraSCSI bus extender on the side
of the StorageWorks shelf.

Remove the power harness and all signal cables from the StorageWorks
backplane and the power transition module and lift it out of the way.

Using a short Phillips head screwdriver, remove the screws holding the backplane
to the back of the shelf and remove from the system.

Replacement
Reverse the steps in the Removal procedure.
Verification
Power up the system. Use the show device console command to verify that the
StorageWorks shelf is configured into the system.

Removal and Replacement 4-39

4.20 StorageWorks UltraSCSI Bus Extender Removal
and Replacement
Figure 4-19 Removing StorageWorks UltraSCSI Bus Extender

StorageWorks
Backplane

UltraSCSI
bus extender
(optional)

UltraSCSI
bus extender

PK1412-99

4-40 AlphaServer DS20 Service Manual

Removal
1.

Shut down the operating system and turn the system off.

Unplug the AC power cords.

Expose the power section of the system. See Section 4.3.

Remove the power and signal cables from the UltraSCSI bus extender on the side
of the StorageWorks shelf.

The UltraSCSI bus extender is mounted on plastic standoffs to which it snaps.
Pinch each snap with a pair of needle nose pliers, free the corners, and pull the bus
extender off.

Replacement
Reverse the steps in the Removal procedure.
Verification
Power up the system. Use the show device console command to verify that the
StorageWorks shelf is configured into the system.

Removal and Replacement 4-41

Appendix A
Halts, Console Commands, and
Environment Variables
This appendix discusses halting the system and provides a summary of the SRM
console commands and environment variables. The test command is described in
Chapter 2 of this document. For complete reference information on other SRM
commands and environment variables, see your system User’s Guide.
NOTE: It is recommended that you keep a list of the environment variable settings for
systems that you service, because you will need to restore certain environment
variable settings after swapping modules. Refer to Table A-4 for a convenient
worksheet.

Halts, Console Commands, and Environment Variables A-1

A.1

Halt Button Functions

The Halt button causes the system to perform in various ways depending upon
the system state at the time the button is pressed.

When the Halt button is pressed, results differ depending upon the state of the
machine. Table A-1 describes the full function of the Halt button.

Table A-1 Results of Pressing the Halt Button
Machine State
OpenVMS running/hung
Compaq Tru64 UNIX running/hung
Windows NT running/hung
AlphaBIOS running/hung
SRM console running
st

SROM (1 2 secs. of pwr-up)
XSROM power-up
SRM console power-up

Result
SRM console runs
SRM console runs
Nothing
Nothing
Sets halt assertion flag: the SRM console
continues to run
Nothing
Sets halt assertion flag, auto boot ignored
Sets halt assertion flag, auto boot ignored

A simple halt causes suspension of a system that is hung or running Compaq Tru64
UNIX or OpenVMS and starts the SRM console.
The halt assertion flag is set in the TOY NVRAM; it is read and cleared by the console
only during power-up or reset. When the SRM console finds the halt assertion flag
set, the conditions of the environment variables auto_action = boot/restart and
os_type = NT are ignored; the SRM console runs and prints the following message:
Halt assertion detected
NVRAM power-up script not executed
AUTO_ACTION=BOOT/RESTART and OS_TYPE=NT ignored, if applicable
P00>>>

A-2 AlphaServer DS20 Service Manual

A.2

Using the Halt Button

Use the Halt button to halt the Compaq Tru64 UNIX or OpenVMS operating
system when it hangs or you want to use the SRM console. Use the Halt button to
force Windows NT systems to bring up the SRM console rather than booting or
halting in AlphaBIOS.

Using Halt to Shut Down the Operating System
You can use the Halt button if the Compaq Tru64 UNIX or OpenVMS operating
system hangs. Pressing the Halt button halts the operating system back to the SRM
console firmware. From the console, you can use the crash command to force a crash
dump at the operating system level.
The Windows NT operating system does not support halts on this system. Pressing
the Halt button during a Windows NT session has no effect.
Using Halt to Clear the Console Password
The SRM console firmware allows you to set a password to prevent unauthorized
access to the console. If you forget the password, the Halt button, with the login
command, lets you clear the password and regain control of the console. See Section
4.8 of your system User’s Guide.

Halts, Console Commands, and Environment Variables A-3

A.3

Halt Assertion

A halt assertion allows you to disable automatic boots of the operating system so
that you can perform tasks from the SRM console.

Under certain conditions, you might want to force a “halt assertion.” A halt assertion
differs from a simple halt in that the SRM console “remembers” the halt. The next
time you power up, the system ignores the SRM power-up script (nvram) and ignores
any environment variables that you have set to cause an automatic boot of the
operating system. The SRM console displays this message:
Halt assertion detected
NVRAM power-up script not executed
AUTO_ACTION=BOOT/RESTART and OS_TYPE=NT ignored, if applicable

Halt assertion is useful for disabling automatic boots of the operating system when
you want to perform tasks from the SRM console. It is also useful for disabling the
SRM power-up script if you have accidentally inserted a command in the script that
will cause a system problem. These conditions are described in the sections
“Disabling Autoboot” and “Disabling the SRM Power-Up Script.”
You can force a halt assertion using the Halt button, the RCM halt command, or the
RCM haltin command. Observe the following guidelines for forcing a halt assertion.
Halt Assertion with Halt Button or RCM Halt Command
Press the Halt button on the local system (or enter the RCM halt command from a
remote system) while the system is powering up or the SRM console is running. The
system halts at the SRM console, and the halt status is saved. The next time the
system powers up, the saved halt status is checked.
NOTE: Wait 5 seconds after the system begins powering up before pressing the Halt
button or remotely entering the RCM halt command.
Halt Assertion with RCM Haltin Command
Enter the RCM haltin command at any time except during power-up. For example,
enter haltin during an operating system session or when the AlphaBIOS console is
running.
If you enter the RCM haltin command during a Compaq TRU64 UNIX or OpenVMS
session, the system halts back to the SRM console, and the halt status is saved. The
next time the system powers up, the saved halt status is checked.
If you enter the RCM haltin command when Windows NT or AlphaBIOS is running,
the interrupt is ignored. However, you can enter the RCM haltin command followed

A-4 AlphaServer DS20 Service Manual

by the RCM reset command to force a halt assertion. Upon reset, the system powers
up to the SRM console, but the SRM console does not load the AlphaBIOS console.
Clearing a Halt Assertion
Clear a halt assertion as follows:
•

If the halt assertion was caused by pressing the Halt button or remotely entering
the RCM halt command, the console uses the halt assertion once, then clears it.

•

If the halt assertion was caused by entering the RCM haltin command, enter the
RCM haltout command or cycle power on the local system.

Disabling Autoboot
The system automatically boots the selected operating system at power-up or reset if
the following environment variables are set:
•

For Compaq Tru64 UNIX and OpenVMS, the SRM environment variables
os_type, auto_action, bootdef_dev, boot_file, and boot_osflags

•

For Windows NT, the SRM os_type environment variable and the Auto Start
selection in the AlphaBIOS Standard CMOS Setup screen

You might want to prevent the system from autobooting so you can perform tasks
from the SRM console. Use one of the methods described previously to force a halt
assertion. When the SRM console prompt is displayed, you can enter commands to
configure or test the system. Chapter 4 of your system User’s Guide describes the
SRM console commands and environment variables.
Disabling the SRM Power-Up Script
The system has a power-up script (file) named “nvram” that runs every time the
system powers up. If you accidentally insert a command in the script that will cause a
system problem, disable the script by using one of the methods described previously to
force a halt assertion. When the SRM console prompt is displayed, edit the script to
delete the offending command. See Section 4.4 of your system User’s Guide for more
information on editing the nvram script.

Halts, Console Commands, and Environment Variables A-5

A.4

Summary of SRM Console Commands

The SRM console commands are used to examine or modify the system state.

Table A-2 Summary of SRM Console Commands
Command

Function

alphabios

Loads and starts the AlphaBIOS console.

boot

Loads and starts the operating system.

clear envar

Resets an environment variable to its default value.

clear password

Sets the password to 0.

continue

Resumes program execution.

crash

Forces a crash dump at the operating system level.

deposit

Writes data to the specified address.

edit

Invokes the console line editor on a RAM file or on the nvram file
(power-up script).

examine

Displays the contents of a memory location, register, or device.

halt

Halts the specified processor. (Same as stop.)

help

Displays information about the specified console command.

info num

Displays various types of information about the system:
Info shows a list describing the num qualifier.
Info 3 reads the impure area that contains the state of the CPU
before it entered PAL mode.
Info 5 reads the PAL built logout area that contains the data used
by the operating system to create the error entry
Info 8 reads the IOD and IOD1 registers.

initialize

Resets the system.

lfu

Runs the Loadable Firmware Update Utility.
Continued on next page

A-6 AlphaServer DS20 Service Manual

Table A-2 Summary of SRM Console Commands (Continued)
Command

Function

Turns off secure mode, enabling access to all SRM console
commands during the current session.

man

Displays information about the specified console command.

Displays a file one screen at a time.

prcache

Initializes and displays status of the PCI NVRAM.

set envar

Sets or modifies the value of an environment variable.

set host

Connects to an MSCP DUP server on a DSSI device.

set password

Sets the console password or changes an existing password.

set rcm_dialout

Sets a modem dialout string.

set secure

Enables secure mode without requiring a restart of the console.

show envar

Displays the state of the specified environment variable.

show config

Displays the configuration at the last system initialization.

show cpu

Displays the state of each processor in the system.

show device

Displays a list of controllers and their devices in the system.

show fru

Displays the serial number and revision level of all options.

show memory

Displays memory module information.

show network

Displays the state of network devices in the system.

show pal

Displays the version of the privileged architecture library code
(PALcode).

show power

Displays information about the power supplies, system fans,
CPU fans, and temperature.

show rcm_dialout

Displays the modem dialout string.

show version

Displays the version of the console program.

start

Starts a program previously loaded on the processor specified.

stop

Halts the specified processor. (Same as halt.)

test

Runs firmware diagnostics for the system.

Halts, Console Commands, and Environment Variables A-7

A.5

Summary of SRM Environment Variables

Environment variables pass configuration information between the console and
the operating system. Their settings determine how the system powers up, boots
the operating system, and operates. Environment variables are set or changed
with the set envar command and returned to their default values with the clear
envar command. Their values are viewed with the show envar command. The
SRM environment variables are specific to the SRM console.

Table A-3 Environment Variable Summary
Environment
Variable

Function

auto_action

Specifies the console’s action at power-up, a failure, or a reset.

bootdef_dev

Specifies the default boot device string.

boot_osflags

Specifies the default operating system boot flags.

com*_baud

Changes the default baud rate of the COM1 or the COM2
serial port.

console

Specifies the device on which power-up output is displayed
(serial terminal or graphics monitor).

cpu_enabled

Enables or disables a specific secondary CPU.

ew*0_mode

Specifies the connection type of the default Ethernet
controller.

ew*0_protocols

Specifies network protocols for booting over the Ethernet
controller.

kbd_hardware_
type

Specifies the default console keyboard type.

kzpsa*_host_id

Specifies the default value for the KZPSA host SCSI bus node
ID.

language

Specifies the console keyboard layout.
Continued on next page

A-8 AlphaServer DS20 Service Manual

Table A-3 Environment Variable Summary (Continued)
Environment
Variable

Function

memory_test

Specifies the extent to which memory will be tested. For
Compaq Tru64 UNIX systems only.

ocp_text

Overrides the default OCP display text with specified text.

os_type

Specifies the operating system and sets the appropriate console
interface.

pci_parity

Disables or enables parity checking on the PCI bus.

pk*0_fast

Enables fast SCSI mode.

pk*0_host_id

Specifies the default value for a controller host bus node ID.

pk*0_soft_term

Enables or disables SCSI terminators on systems that use the
QLogic ISP1020 SCSI controller.

sys_model_num

Displays the system model number and computes certain
information passed to the operating system. Must be restored
after the system board is replaced.

sys_serial_num

Restores the system serial number. Must be set if the system
board is replaced.

sys_type

Displays the system type and computes certain information
passed to the operating system. Must be restored after the
system board is replaced.

tga_sync_green

Specifies the location of the SYNC signal generated by the
DIGITAL ZLXp-E PCI graphics accelerator option.

tt_allow_login

Enables or disables login to the SRM console firmware on
other console ports.

Halts, Console Commands, and Environment Variables A-9

A.6

Recording Environment Variables

This worksheet lists all environment variables. Copy it and record the settings
for each system. Use the show* command to list environment variable settings.

Table A-4 Environment Variables Worksheet
Environment
Variable

System Name

auto_action
bootdef_dev
boot_osflags
com1_baud
com2_baud
console
cpu_enabled
ew*0_mode
ew*0_protocols
kbd_hardware_
type
kzpsa*_host_id
language
memory_test
ocp_text
os_type
pci_parity
pk*0_fast
pk*0_host_id

A-10 AlphaServer DS20 Service Manual

System Name

Table A-4 Environment Variables Worksheet (Continued)
Environment
Variable

System Name

pk*0_soft_term
sys_model_num
sys_serial_num
sys_type
tga_sync_green
tt_allow_login

Halts, Console Commands, and Environment Variables A-11

Appendix B
Managing the System Remotely
This appendix describes how to manage the system from a remote location using the
remote console manager (RCM). You can use the RCM from a console terminal at a
remote location or from a local console terminal connected to the COM1 port.
Sections in this appendix are:
•

RCM Overview

•

First-Time Setup

•

RCM Commands

•

Using the RCM Switchpack

•

Troubleshooting Guide

Managing the System Remotely B-1

B.1

RCM Overview

The remote console manager (RCM) monitors and controls the system remotely.
The control logic resides on the system board.

The RCM is a separate console from the SRM and AlphaBIOS consoles. The SRM
and AlphaBIOS firmware reside on the system board. The RCM firmware resides on
the server feature module and can only be accessed through COM1. The RCM is run
from a serial console terminal or terminal emulator. A command interface lets you
reset, halt, and power the system on or off, regardless of the state of the operating
system or hardware. You can also use RCM to monitor system power and
temperature.
You can invoke the RCM either remotely or through the local serial console
terminal. Once in RCM command mode, you can enter commands to control and
monitor the system. Only one RCM session can be active at a time.
•

To connect to the RCM remotely, you dial in through a modem and then type an
escape sequence that invokes RCM command mode. You must set up the
modem before you can dial in remotely.

•

To connect to the RCM locally, the console terminal has to be connected to
COM 1 and then you type the escape sequence at the SRM console prompt on
the local serial console terminal to enter RCM mode.

CAUTION: Do not issue RCM commands until the system has powered up. If you
enter certain RCM commands during power-up or reset, the system may hang. In
that case you would have to disconnect the power cord at the power outlet. You can,
however, use the RCM halt command during power-up to force a halt assertion. See
Section A.3 for information on halt assertion.

B-2 AlphaServer DS20 Service Manual

B.2

First-Time Setup

To set up the RCM to monitor a system remotely, connect the modem to the
COM1 port at the back of the system, configure the modem for autoanswer and
9600 baud, and dial in.

Figure B-1 RCM Connections

PK1473-98

Managing the System Remotely B-3

B.2.1

Using RCM Locally or with a Modem on COM1

Use the default escape sequence to invoke the RCM mode locally for the first time.
You can invoke RCM from the SRM console, the operating system, or an
application. The RCM quit command reconnects the terminal to the system console
port.
1.

To invoke the RCM locally, type the RCM escape sequence. See ➊ in Example
B–1 for the default sequence.
The escape sequence is not echoed on the terminal or sent to the system. At the
RCM> prompt, you can enter RCM commands.

To exit RCM and reconnect to the system console port, enter the quit command
(see ➋). Press Return to get a prompt from the operating system or system
console.

Example B–1 Invoking and Leaving RCM Locally
P00>>> ^]^]rcm
RCM>

➊

➋
RCM> quit
Focus returned to COM port

B-4 AlphaServer DS20 Service Manual

B.3

RCM Commands

The RCM commands given in Table B-1 are used to control and monitor a
system remotely.

Table B-1 RCM Command Summary
Command

Function

halt

Halts the server. Emulates pressing the Halt button and
immediately releasing it.

haltin

Causes a halt assertion. Emulates pressing the Halt button and
holding it in.

haltout

Terminates a halt assertion created with haltin. Emulates releasing
the Halt button after holding it in.

help or ?

Displays the list of commands.

poweroff

Turns off power. Emulates pressing the On/Off button to the off
position.

poweron

Turns on power. Emulates pressing the On/Off button to the on
position.

quit

Exits console mode and returns to system console port.

reset

Resets the server. Emulates pressing the Reset button.

setesc

Changes the escape sequence for invoking command mode.

status

Displays system status and sensors.

Managing the System Remotely B-5

Command Conventions
•
•
•
•
•

The commands are not case sensitive.
A command must be entered in full.
You can delete an incorrect command with the Backspace key before you press
Enter.
If you type a valid RCM command, followed by extra characters, and press
Enter, the RCM accepts the correct command and ignores the extra characters.
If you type an incorrect command and press Enter, the command fails with the
message:
*** ERROR - unknown command ***

halt
The halt command halts the managed system. The halt command is equivalent to
pressing the Halt button on the control panel and then immediately releasing it. The
RCM firmware exits command mode and reconnects the user’s terminal to the
system COM1 serial port.
RCM>halt
Focus returned to COM port
The halt command can be used to force a halt assertion. See Section A.3 for
information on halt assertion.
NOTE: If you are running Windows NT, the halt command has no effect.
haltin
The haltin command halts a managed system and forces a halt assertion. The haltin
command is equivalent to pressing the Halt button on the control panel and holding
it in. This command can be used at any time after system power-up to allow you to
perform system management tasks.
NOTE: If you are running Windows NT, the haltin command does not affect the
operating system session, but it does cause a halt assertion.
haltout
The haltout command terminates a halt assertion that was done with the haltin
command. It is equivalent to releasing the Halt button on the control panel after
holding it in (rather than pressing it once and releasing it immediately). This
command can be used at any time after system power-up.

B-6 AlphaServer DS20 Service Manual

help or ?
The help or ? command displays the RCM firmware commands.
poweroff
The poweroff command requests the RCM to power off the system. The poweroff
command is equivalent to pressing the On/Off button on the control panel to the off
position.
RCM>poweroff
If the system is already powered off or if switch 3 (RPD DIS) on the switchpack has
been set to the on setting (disabled), this command has no immediate effect.
To power the system on again after using the poweroff command, you must issue the
poweron command.
If, for some reason, it is not possible to issue the poweron command, the local
operator can start the system as follows:
1.

Press the On/Off button to the off position and disconnect the power cord.

Reconnect the power cord and press the On/Off button to the on position.

poweron
The poweron command requests the RCM to power on the system. The poweron
command is equivalent to pressing the On/Off button on the control panel to the on
position. For the system power to come on, the following conditions must be met:
•

AC power must be present at the power supply inputs.

•

The On/Off button must be in the on position.

•

All system interlocks must be set correctly.

The RCM exits command mode and reconnects the user’s terminal to the system
console port.
RCM>poweron
Focus returned to COM port
NOTE: If the system is powered off with the On/Off button, the system will not
power up. The RCM will not override the “off” state of the On/Off button. If the
system is already powered on, the poweron command has no effect.

Managing the System Remotely B-7

quit
The quit command exits the user from command mode and reconnects the serial
terminal to the system console port. The following message is displayed:
Focus returned to COM port
Upon entering a carriage return, the system returns to either the console or the
operating system depending upon which was running when the RCM was invoked.
reset
The reset command requests the RCM to reset the hardware. The reset command is
equivalent to pressing the Reset button on the control panel.
RCM>reset
Focus returned to COM port
The following events occur when the reset command is executed:
•

The system restarts and the system console firmware reinitializes.

•

The console exits RCM command mode and reconnects the serial terminal or
console monitor to the system COM1 serial port.

•

The system executes its normal power-up sequence.

setesc
The setesc command resets the default escape sequence for invoking RCM. The
escape sequence can be any character string. A typical sequence consists of 2 or
more characters, to a maximum of 15 characters.
NOTE: Be sure to record the new escape sequence. Although the factory defaults
can be restored if you forget the escape sequence, this requires resetting the EN
RCM switch on the RCM switchpack.
The following escape sequence consists of 5 iterations of the Ctrl key and the letter
“o”.
RCM>setesc
^o^o^o^o^o
RCM>
If the sequence entered exceeds 15 characters, the command fails with the message:
*** ERROR ***
When changing the default escape sequence, avoid using special characters that are
used by the system’s terminal emulator or applications.
Control characters are not echoed when entering the escape sequence. Use the status
command to verify the complete escape sequence.
B-8 AlphaServer DS20 Service Manual

status
The status command displays the current state of the system sensors, as well as the
current escape sequence and alarm information. The following is an example of the
display.
RCM>status
Firmware Rev: V2.0
Escape Sequence: ^]^]RCM
Remote Access: ENABLE
Temp (C): 26.0
RCM Power Control: ON
RCM Halt: Deasserted
External Power: ON
Server Power: ON
RCM>
The status fields are explained in Table B-2.

Table B-2 RCM Status Command Fields
Item

Description

Firmware Rev:

Revision of RCM firmware.

Escape Sequence:

Current escape sequence to invoke RCM.

Remote Access:

Modem remote access state. (ENABLE/DISABLE)

Temp (C):

Current system temperature in degrees Celsius.

RCM Power Control:

Current state of RCM system power control. (ON/OFF)

RCM Halt:

Asserted indicates that halt has been asserted with the
haltin command. Deasserted indicates that halt has
been deasserted with the haltout command or by
cycling power with the On/Off button on the control
panel. The RCM Halt: field does not report halts
caused by pressing the Halt button.

External Power:

Current state of power to RCM. Always on.

Server Power:

Indicates whether power to the system is on or off.

Managing the System Remotely B-9

B.4

Using the RCM Switchpack

The RCM operating mode is controlled by a switchpack on the server feature
module located in the fan area between the system card cage and the front of the
system. Use the switches to enable or disable certain RCM functions, if desired.

Figure B-2 Location of RCM Switchpack on Server Feature
Module

12 34

RCM
Switchpack

PK1472-98

Switch

Name

Description

EN RCM

Enables or disables the RCM. The default is ON
(RCM enabled). The OFF setting disables RCM.

Reserved

RPD DIS

Enables or disables remote poweroff. The default is
OFF (remote poweroff enabled).

SET DEF

Sets the RCM to the factory defaults. The default is
OFF (reset to defaults disabled).

B-10 AlphaServer DS20 Service Manual

Uses of the Switchpack
You can use the RCM switchpack to change the RCM operating mode or disable the
RCM altogether. The following are conditions when you might want to change the
factory settings.
•

Switch 1 (EN RCM)—Set this switch to OFF (disable) if you want to reset the
baud rate of the COM1 port to a value other than the system default of 9600.
You must disable RCM to select a baud rate other than 9600.

•

Switch 2 (Reserved)—Reserved.

•

Switch 3 (RPD DIS). Set this switch to ON (disable) if you want to disable the
poweroff command. With poweroff disabled, the monitored system cannot be
powered down from the RCM.

•

Switch 4 (SET DEF). Set this switch to ON (enable) if you want to reset the
RCM to the factory settings. See the section “Resetting the RCM to Factory
Defaults.”

Changing a Switch Setting
The RCM switches are numbered on the server feature module. The default
positions are shown in Figure B-2. To change a switch setting:
1.

Turn off the system.

Unplug the AC power cords.
NOTE: If you do not unplug the power cords, the new setting will not take effect
when you power up the system.

Remove the system covers. See Section 4.3.

Locate the RCM switchpack on the server feature module and change the switch
setting as desired.

Replace the system covers and plug in the power cords.

Power up the system to the SRM console prompt and type the escape sequence
to enter RCM command mode, if desired.

Managing the System Remotely B-11

Resetting the RCM to Factory Defaults
You can reset the RCM to factory settings, if desired. You would need to do this if
you forgot the escape sequence for the RCM. Follow the steps below.
1.

Turn off the system.

Unplug the AC power cords.
NOTE: If you do not unplug the power cords, the reset will not take effect when
you power up the system.

Remove the system covers. See Section 3.2.

Locate the RCM switchpack on the server feature module and set switch 4 to
ON.

Replace the system covers and plug in the power cords.

Power up the system to the SRM console prompt.
Powering up with switch 4 set to ON resets the escape sequence, password, and
modem enable states to the factory defaults.

Power down the system, unplug the AC power cords, and remove the system
covers.

Set switch 4 to OFF.

Replace the system covers and plug in the power cords.

10. Power up the system to the SRM console prompt, and type the default escape
sequence to invoke RCM command mode:
^]^]RCM

B-12 AlphaServer DS20 Service Manual

B.5

Troubleshooting Guide

Table B-3 is a list of possible causes and suggested solutions for symptoms you
might see.

Table B-3 RCM Troubleshooting
Symptom

Possible Cause