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AV-JB904-A8

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Document:	VT100 and PDT-11 Video Terminals Maintenance A Self-Paced Lab Course
Order Number:	AV-JB904-A8
Revision:	0
Pages:	48
Original Filename:

OCR Text

/—-\

VT100 and PDT-11
VideoTerminals Maintenance
A Seli~-Paced/Lab Course
Introduction

e A

)

Physical/Functional Description

1979 by Digital Equipment Corporation

The material in this manual is for informational purposes and
is subject to change without notice.
Digital Equipment Corporation assumes no responsibility for
any errors which may appear in this manual.

Printed in U.S.A.

The following are trademarks of Digital Equipment Corporation,
Maynard, Massachusetts:

DIGITAL
DEC
PDP
DECUS
UNIBUS

MASSBUS
OMNIBUS
0S/8
RSTS
RSX

DECsystem-10
DECSYSTEM-20
DIBOL
EDUSYSTEM
VAX
VMS

IAS

DIGITAL

VT100 AND PDT-11

AV-JB904-AS8

VT100 AND PDT-11 VIDEO TERMINALS MAINTENANCE

INTRODUCTION

(AV-JB904-A8)

-FOR

INTERNAL

USE

ONLY-

VT100

DIGITAL

AND

PDT-11

AV-JB994-A8

COURSE MAP

PDT-11/130
INTELLIGENT

TERMINAL
*

VT105

PDT-11/110

GRAPHICS

INTELLIGENT

TERMINALTM

(553)
&

\JERMINAL

VT100

FAULT

REMOVE/
REPLACE

ISOLATION

VT100

OPTIONS

OPERATION
AND

ACCEPTANCE

INSTALLATION

AND

SETUP

PHYSICAL/
FUNCTIONAL
DESCRIPTION

THEORY OF

OPERATIONTM

* To be provided in a course update.

MA-2734

IN-i1

-FOR

INTERNAL

USE

ONLY-

DIGITAL

VT10@ AND PDT-11
AV-JB904-A8

INTRODUCTION

CONTENTS
....ccceceoccooecocscssoacssosooscsossoccsscssoes

IN-1

General DesSCription .c.ceecececescocccccscscccscscocsos cooee
FeatUresS .cccececocoocccoosososoccooscccocsoocosscscscssssocossosee
VT100 Specifications ..c.ccececeecoccocccsosscsossocoscos

Introduction

IN—-2
IN-3
IN-6

VT10@

IN-8

OptiONS

. .ceeeeocoescoscscososcsssscsscssssssoccscssse

IN-iii

—FOR

INTERNAL

USE

ONLY-

DIGITAL

VT10@0 AND PDT-11
AV-JB904-A8

INTRODUCTION
This

module

will

supply

vyou

with

general

description
of
the
capabilities,
the
physical
and
electrical specifications, and the basic functions of the
VT10@ video terminal.
You will not be tested on this

module but
it does provide you with
information which
will be valuable in interfacing with your customers.
In

order

1install

and

maintain

the

VT108

video

terminal, you should understand what the basic VT100 is
capable of doing, which features are standard, and which
features are optional.

The basic VT100 is the first member of a new family
ASCII
alpha-numeric
video
display
terminals
being

developed

CORPORATION.

and

The

manufactured

purpose

the

DIGITAL

VT100

EQUIPMENT

provide

basic modular video display terminal system which can be
field upgradable from a low cost, simple video terminal
to a smart or even an intelligent video terminal through
the addition of optional printed circuit boards
(PCBs)
and yet be highly serviceable and easy to repair.

IN-1

-FOR

INTERNAL

USE

ONLY-

VT1006 AND PDT-11

DIGITAL =

AV-JB904-A8

GENERAL DESCRIPTION
The basic VT100 video terminal is a self-contained desk

top unit which consists of a 12" Cathode Ray Tube (CRT)
Monitor, a single 18" X 10" printed circuit board
Hz power supply,
controller, a 95 watt, 116/220 volt, 47-63
assembly
monitor
CRT
The
keyboard.
detached
key
83
a
and
See
pounds.
4.5
weighs
keyboard
the
and
pounds
30
weighs
Figure 1 for the physical dimensions of the VT100.

36.8 CM

{14 1/2 IN.)

. 8.9 Cwm

(3 1/2 IN)) f

ln 7/8 IN.) \
4.8 CM

!
- 111CMIN.)‘J
L—(4 3/8

‘

—J
]
L—24.5 CcM (9 5/8 IN.)—J
30.5 CM (12 IN.)

le——20.32 CM (8 IN.) e

36.2 CM (14 1/4 IN))
51.4-CM (20 1/4 IN.")

41.3 CM (16 1/4 IN))

J
X

45.7CM (18 IN.)

*MEASUREMENT TAKEN WITH THE KEYBOARD PLACED FLUSH TO FRONT OF TERMINAL UNDER UNDERCUT.
MA-1991

Figure 1.

VT100 Physical Dimensions

IN-2

-FOR INTERNAL USE ONLY-

VT10¢ AND PDT-11

DIGITAL

AV-JB904-A8

FEATURES
The VT100
1.
2.

controller

PCB

contains

the

logic

control the terminal;
dJgenerate the display presnntatlon,

to:

and

handle the communications with the host computer
over an Electronics Industry Association (EIA)
compatible modem.

The

basic VT100

can display

information

column

by 24 line format or in a 132 column by 14 line format.
This is selectable by the operator or the host computer. The
character generator can produce both the standard US and the
United Kingdom character sets, six displayable control codes
(graphic
representations of
the Horizontal Tab,
Vertical
Tab, Carriage Return, Line Feed, Form Feed, and New Line
functions),
and displayable line segments which allow the
terminal to be used for very limited graphics.

The characters displayed on the screen are formed using
7X9 dot matrix (Figure 2) and can be displayed as white

characters
white

dark

background

black

characters

background.

The

displayed

underline

VT100

also

provides

choice

the

screen.

can

block

video

which

the

type

either

the

opposite

cursor

flashing
of

the

screen background.

SCAN NUMBER

10 DOTS

1l++ 44 dt24a alrsvtt s 4444l
2

+++ 1@+ +++

+++@+@+++ ++4++t+t44+14++4++

+ 144+
H

++@+++@++
10+ 0O G+
+

+@++++1@+

0000000+
+ +0®+++ +@++ +

+ +@@+++ 4@+
4

74@+-+ ++4+0++
+@ + 0009+ + + +
8

+@+++++@+
4+ +@ + +4+ + 4+ + + 4+ 4

1 ++4+44++++4+@
+ +4 4+ 44+ 4+ 4+

++4+++4+4+4++41+@+
+4++ 444+ 4+ 4+

UNDERLINE
SCAN

J
MA-2973

Figure

Character

Presentation

IN-3

-FOR

Technique

INTERNAL USE ONLY-

DIGITAL

VT100 AND PDT-11
AV-JB904-A8

Another

feature

the

basic

VT1080

the

ability

highlight
important
information on the display either
by
underlining the information or by displaying the information

as the reverse of that used to display the normal screen
presentation.
The type of cursor selected in SET-UP mode,
underline or reverse, controls which highlighting feature 1is
to
be
used.
The
selected
highlighting
feature
1is
then
turned
on
by
receiving
either
the
escape
sequence
to
underscore (underline) or to reverse video.
All

information

will be displayed
cursor, regardless

stop

which

follows

either

escape

with the same highlight
of which escape sequence

the highlighting of

information,

sequence

features as
is received.

the VT100 must

the
To

receive

an
escape
sequence
to
turn
of
all
highlighting.
These
escape
sequences
are
contained
in
the
OPERATION
AND
ACCEPTANCE Module (AV-JB910-A8) of this course.

the

Under

the

control

VT1l0@

can

display

1lines

the

operator
of

the

characters

host
that

computer,
are

twice

their normal size in both height and width or in width only.
These
features
are
called Double Height-Double Width,
and"
Double Width-Single
Height
respectively.
When
using
these
modes

the

amount

information

the

screen

reduced,

the

number

lines.

The

VT100

formation

Scrolling

both

terminal

the

vertical

which

the

provides

screen:

the

jump

two

information to make room for

the

modes

scroll

movement

can

number

the

and

the

new

presented

columns

and

scrolling
smooth

in-

scroll.

existing

lines.

lines

Jjump

scroll
mode
information
appears
to
Jjump up
or
down
the
screen a line at a time.
In the smooth scroll mode the
information moves one tenth of a chararacter line at a time,
yizlding a very smooth movement to the data, thus resulting
in reading ease.
The type of scrolling used is the choice
operator

the

host

computer

system.

The VT100
communicates
with
the
host
computer
using
full
duplex,
serial
asynchronous
transmission.
In
full
duplex, information can be transmitted to and received from

the host computer
transmission means

represent

unit

at the same time.
Serial asynchronous
that the seven or eight bits required to

information

(character)

sequentially and is framed by a start bit and
that the characters can be separated in time.

IN-4

-FOR

transmitted
stop

INTERNAL

USE

bit

ONLY-

VT1006 AND PDT-11

DIGITAL

AV-JB904-A8

The VT1008 can receive from and transmit to a host
computer at speeds anywhere from 50 to 19,200 baud (bits per
The receiver can be using a different speed than
second) .
the transmitter. The possible baud rates are 50, 75, 1160,
134, 150, 200, 300, 600, 1200, 1800, 2000, 2400, 4800, 9600,
and

19200.

The basic VT100

also provides a choice as to the number

of bits per character (7 or 8) used in transmission and
reception of data to and from the host. The customer also
has a choice of having parity enabled or disabled, and if
parity is enabled a choice as to whether to use an odd or

even parity check. Parity checking and generation is a means
used to detect single bit errors during the transmission of

data to and from the host computer. The
during
communications
is
the American
Information

Interchange

The VT100 has

character set used
Standard
Code
for

(ASCII)

only

two

switches

the

unit:

the power

on/off switch (S1) and a voltage
range
selection
switch
(S2).
All other features which would normally be set with
switchesor jumpers
(such
as
the baud
rates,
ac
line
frequency, bits per character,
etc.)
are stored in a
non-volatile random access memory (NVR).

which

The

VT100

verifies

has

power-up

the major

internal

functions of

diagnostic

the

feature

terminal when the

terminal
is
first
turned
on.
There
are
two
additional
internal diagnostics which, in conjunction with two special
loop-back connectors, can check the communication interface
to

ensure

that

intact.

See
Table
I-1
for
electrical specifications

a
of

summary
of
the VT100.

IN-5

-FOR

the

physical

INTERNAL

USE

and

ONLY-

DIGITAL

VT10@

AND PDT-11

AV-JB904-A8

Table

VT100

Specifications

(Sheet

Height:

36.8

Width:
Depth:

45.7
36.2

cm- (18 in)
cm (14.25 in)

Height:
Width:
Depth:

8.9
45.7
20.3

cm
cm
cm

Dimensions
Monitor

Keyboard

(14.5

in)

(3.5 in)
(18 in)
(8 1in)

Minimum Table

Depth:

51.435

(20.25

in)

Weight
Monitor

13.6

(30

Keyboard

2.0

(4.5

18.6

(41

Shipping

Weight

1lbs)
1lbs)

1bs)

“Environment-

Operating

Temperature 16° ¢ to 40° C

to 104° F)

Relative

Humidity

Altitude

2.4

10%

(50O F

90%

Maximum Wet Bulb 28> C (82 F)
Minimum Dew Point 2~ C (36O F)
Non-Operating

(8,000

ft)

Tempgrature -4g0 C to 66° C
(=40~

151"

Relative

Humidity

Altitude

9.1

0 to 95%
(30,000 ft)

Power

Line Voltage

99 - 128 V RMS single phase, 2
wire
180 - 256 V RMS single phase, 2
wire

Line Frequency
Current

Input Power Current Limiting
Power Cord

(Switch Selectable)
47 - 63 Hz
3.0 A RMS maximum at

115

1.5

230

RMS maximum

V RMS
V RMS

250 VA apparent 150 Watts maximum
3 A normal blow fuse
detachable, 3 prong, 1.9 meters
(6 £t)
IN-6

-FOR

INTERNAL

USE

ONLY-

VT10@0 AND PDT-11

DIGITAL

AV-JB904-A8

VT100 Specifications

Table 1.

(Sheet 2 of 2)

Display
CRT

Format

phosphor
24 lines

diagonal

measure

x 80 characters or
14 lines x 132 characters
|
(Selectable)

7 x 9 dot matrix with descenders

Character

size

Active Display Size
Character

Cursor

Set

Type

column mode:

3.35 mm X

2.0 mm (0.13 in x 0.078 in)
in 132 column mode: 3.35 mm X
1.3 mm (0.13 in x @0.0651 in)
202 mm X 115 mm (8 in x 4.5 in)
96 character displayable ASCII
subset (upper and lower case,
numeric, and punctuation.)
Keyboard selectable blinking
block character or blinking
underline.

IN-7

—-FOR

INTERNAL

USE

ONLY-

DIGITAL

VT10@8 AND PDT-11
AV-JB904-A8

VT100 OPTIONS
At

the

available.

Current

present

These

Loop

time

are

the

VT100

has

two

option

Advanced Video Option

Communication Option.

and

which

are

the

20ma

The Advanced Video Option
(AVO)
is a plug-in module
which mounts on the Terminal Controller PCB and provides;
additional memory to allow
a 24 line by 132 column screen
format, space for additional Read-Only program memory, the
ability to have a second character generator chip installed
on

the

Terminal

The

AVO

Controller.

also

provides

additional

ways

highlighting

important
character

information
on
the
screen
on
a
character
basis.
These additional highlighting features

by
are.
the ability to blink information and to make the information
brighter
(Bold).
Also with the AVO installed the VT100 can
use both underscore and reverse video,
independent of the
type of cursor selected.
This provides more capability than
that
offered
with
the
basic
VT100.
All
of
the
above
highlighting features can be used independently or 1in any
and
all
combinations
giving
the
customer
up
to
sixteen
different

ways

making

information

stand

out.

The 20mA Current Loop Communications Option allows the
terminal
to
communicate
over
a
20mA
current
loop
communication
facility
to
the
host
processor
instead
of
using the standard EIA interface which normally requires the
use
of
modems.
This
option
1is
normally
used
when
the
terminal is in the same building as the host computer while
modems are used when you must go over dgreater distances.
In

the

future

other

options

will

added

the

VT100,

some of these options will possibly be a printer adapter, an
internal modem, other communications options, etc.
As these
different
options
are
added
to
the
equipment
new
course
modules
will
be
added
to
this
course's
OPTION
and
FAULT
ISOLATION sections.
All you will then need to do is study
the new modules, if you are proficient with the basic course
material which you will cover in the following modules.

IN-8

~FOR INTERNAL USE ONLY-

DIGITAL

VT100 AND PDT-11

AV-JB904-A8

VT100 AND PDT-11 VIDEO TERMINALS MAINTENANCE

PHYSICAL/FUNCTIONAL DESCRIPTION

(AV-JB904-A8)

-FOR

INTERNAL

USE

ONLY-

VT10@0 AND PDT-11

DIGITAL

AV-JB904-A8

COURSE MAP

PDT-11/130
INTELLIGENT

"TERMINAL
*

VT105

PDT-11/110

GRAPHICS

INTELLIGENT

TERMINAL

REMOVE/

VT100

REPLACE

OPTIONS

OPERATION

AND

ACCEPTANCE

INSTALLATION

THEORY OF

OPERATIONTM

* To be provided in a course update.

INTRODUCTION

MA-2734

PF-ii

-FOR

INTERNAL

USE

ONLY-

DIGITAL

VT100 AND PDT-11
AV-JB904-A8"

Physical/Functional Description
CONTENTS
Introduction

....cccececccoccsscocccscscccocses s ecocsace

Objective
Objective
RESOUIXCES

PF-1

and Sample Test Item #1 ....... creccoec
s
and Sample Test Item #2 ........ boo os
e e
ccceooceccososcososccscssssocosscssssose s ecoeos
ese
The Field Replaceable Units ..ccccecoccces cepocococsnoe
Power Supply Assembly ..ccccecccecccccccns eoo esc
s
DC Power Harness .c.ececcececoccocscocc ceocecoccasses e
Terminal Controller PCB .ccceccecocccccse ceeoeec o
Video Monitor PCB ...cccececoccccossccocscse s eoes
o ee
Flyback Transformer ....cceccoe cecocccne csoccc
e o

PF-3
PF-5
PF-6
PF-7
PF-8
PF-10
PF-11
PF-13
PF-17

Field Service Replacement CRT Monltor Assemblv

PF-18

VT103

Keyboard

...cccccececocccocccsccccccscos cecoecc
s

PF-19

. .ceeecesccoccococcsosscssocccsccccssos

PF-20-

SPEAKEL c et eesoococcooccsocoosssssosssssocccoscssos
Keyboard Cable ...cccceeccccccoccococcssoccososssscoese

PF-20
PF-20

Keyboard PCB

Practice

Exercise

....... e eescessesesess
st s sen e

PF-21

Practice

Exercise

SOlutions

PF-28

....ccececeecceccccccccocses

PF-i1ii

-FOR

INTERNAL USE

ONLY-

DIGITAL

VT10@ AND PDT-11
AV-JB904-A8

Physical/Functional Description

INTRODUCTION
This

module

one

the

key

elements

which

will

enable
you
to
perform
the major
maintenance
tasks
associated
with
the VT100.
These major
tasks
are
diagnosing and
isolating problems,
locating the faulty
FRU,
removal
and
replacement
then the verfication that the
by operating the terminal.
The

purpose

this

of
the
suspected
problem has been

learning

module

FRU and
repaired

assist

in the identification, location, and understanding
major
functions
of
the
FIELD REPLACEABLE
UNITS

you

of the
(FRUs)

which
make
up
the
Basic
VT100
video
terminal.
The
knowledge
of
the physical
and
functional
relationships
which you will gain in this module is a building block.
towards the total understanding you will need to maintain
the VT100 Based Video terminals.

PF-1

-FOR

INTERNAL

USE

ONLY-

VT104 AND PDT-11

DIGITAL

This page

AV-JB904-A8

for

notes.

PF-2

-FOR INTERNAL USE ONLY-

VT100 AND PDT-11

DIGITAL

AV-JB904-A8

OBJECTIVE 1
Provided with

the

name

the

Field

Replacement

Unit

and a selection of functional descriptions match each

FRU

its major

function.

The Field Replacement Units
Power
DC

are:

Supply

Power

Terminal

Harness

Controller

PCB

Video Monitor PCB
Flyback Transformer

Field Service CRT Monitor Assy.

Keyboard
Keyboard

PCB
Cable

Speaker

SAMPLE TEST ITEM 1

—

Provided with the name of the Field Replacement Unit
and a selection of functional descriptions match each
Blacken the letter in
FRU to its major function.
front

FIELD

REPLACEMENT

Terminal

your

response.

UNIT

Controller

FUNCTIONAL DESCRIPTION

Controls

the

presentation

CRT
only.

Emulates

the VT52 Video

Terminal

only.

Controls the flow of
information to the host
computer only.

Controls

the

flow

information

from the

Keyboard

the

host

computer and from the
host computer to the CRT
screen.

PF-3

—-FOR

INTERNAL

USE

ONLY-

DIGITAL

VT100 AND PDT-11
AV-JB904-A8

This

page

for

notes.

PF-4

-FOR

INTERNAL

USE

ONLY-

VT160 AND PDT-11

DIGITAL

AV-JB904-A8

OBJECTIVE 2
Provided with the Connector number and a selection of
functional descriptions for the connectors on the
Terminal Controller and Video Monitor PCBs match each
its

connector to

The

connector

numbers

are:.

®
@
®

J1l
J3
J5

@
@
@

J2
J4
J6

@
@

J9
J102

®
®

J101
J1l104

““““

function.

SAMPLE TEST ITEM 2
Provided with the Connector number and a selection of
functional descriptions match each connector to 1its
Blacken out the letter in front of your
function.
response.

Connector Number
J1l

Connector Function
A.

External Video
input
tion.

connec-

Connection point
for the 20 mA
current loop
communication
option.

Connection point
for

the

Keyboard

cable.

PF-5

Connection point
for the advanced
Video option.

-FOR

INTERNAL USE ONLY-

DIGITAL

VT100

AND

PDT-11

AV-JB904-A8

RESOURCES
VT100

Mini

Maintenance

VT1080@0

User

Guide

Hardware

Guide

EK-VT100-J1-001

EK-VT100-UG-001

PF-6

-FOR

INTERNAL

USE

ONLY-

DIGITAL

VT10@ AND PDT-11

AV-JB9@4-A8

Physical/Functional Description
THE FIELD REPLACEABLE UNITS
The
(FRUs) .

FRUs

follows:

Power

Supply Assembly
Harness

Terminal

Controller

PCB

Video

Monitor

Field

Service Replacement CRT Monitor Assembly

Flyback

Transformer

Keyboard
Speaker

PCB

Keyboard

Cable

The

Physical/Functional

physically

Block

Diagram,

Mini Maintenance Hardware Guide,

VT10@

identify

each

3)
4)

found

help you:

1in

the

FRU

identify each connector and its function
determine the interrelationship of the FRUs.

this

time

locate

each

addition

these

which are considered
units

(AV-JB9%14-A8)
VT106

will

the

FRU on

nine

FRUs when
covered

FRUs

there

installed

1in

course.

the

Diagram.

Block

Physical/Functional

basic

will

identify each FRU by part number

These

FRUs

nine

Power

The

module.

this

covered

will

these
are

nine Field Replaceable Units
physical locations of each of

VT10@ consists of
The functions and

the

This

are

optional

units

in the basic VT100.

VT1¢0@

module

OPTIONS

deals

only.

Module

with

the

PF-7

-FCR

INTERNAL

USE

ONLY-

DIGITAL

VT100 AND PDT-11
AV-JB904-A8

POWER SUPPLY ASSEMBLY P/N 70-14979
The

VT100

under
the
physically

Power

Supply

considered

one-piece

recommended
maintenance
philosophy.
located in the lower left rear corner of

Monitor Chassis
(POP) fasteners

and is held
(Figure 1).

place

three

unit

It
is
the CRT

expansion

lock

POWER SUPPLY

/P/N 70-14979

3 POP

FASTENERS

FUSE (F1)

S1 POWER ON/OFF SWITCH

S2 VOLTAGE SELECTION
SWITCH
AC POWER

RECEPTACLE

Figure

The
either

VT100
110V

VT100

Power

(90V

Supply
128V)

MA-2974

Power

Supply

1is

capable

220V

Location

(180V to

operating

256V)

volts

with
ac

a frequency of 47 to 63 Hz,.
The voltage selection switch
(52)
is a slide switch located on the Power Supply next to
the input power connector.
The switch is labeled so that it
displays
the
voltage
range
selected.
To match
the
Power
Supply
to
the
screwdriver
to

display

the

available
slide
the

correct

voltage

ac
voltage
simply
switch
either 1left

range.

The

PF-8

-FOR

second

use
or

a
small
right
to

switch

INTERNAL

USE

the

ONLY-

DIGITAL

VT100 AND PDT-11

‘

AV-JB904-A8

power supply is the Power ON/OFF toggle switch

(S1) and 1is

Also located
located above the ac input power recepticle.
is used to
which
(F1l)
fuse
line
the
is
Supply
Power
the
on
The Power
power.
much
to
drawing
from
unit
the
protect
fuse.
acting
normal
AMPS,
3.0
a
by
protected
is
Supply
Using

and

Figure

Physical/Functional

the

Block Diagram locate the following:
.

Recepticle

Voltage Selection switch(S2)
Power

ON/OFF

Fuse

(F1)

Pop

The

switch(S1)

Fastners

function

Power

the

voltages

1is

Supply

the

convert

line voltage into four dc voltages needed to operate the
All output
The power supply has no adjustments.
terminal.
This means that 1if the
voltages are over-current protected.
unit draws to much current from the supply regulators the
power supply will automatically reduce the output current
and voltage to protect the regulator circuits from being
destroyed.

The

developed

the

power

supply

1is

used

are:

Vdc

Terminal
the

11.0

AMPS

Controller

maximum

and

any

which

options

which

plug

the

into

Controller.

+12 Vdc at
Terminal

PCB

and

-12

Vdc

Terminal

2.75 AMPS maximum which

Controller,

the

CRT

the

Keyboard,

filament voltage.

AMPS

maximum

which

used

the Video

the

Controller.

-23 Vdc at 10 milliamps maximum which is used
the Terminal Controller for the NVR memory.

the

All the dc voltages are fed out
edge connector which plugs into

the

Power

by the

Monitor

only by

of the power supply via
the 18 pin connector of

Harness.

PF-9

-FOR

INTERNAL

USE

ONLY-

DIGITAL

VT100

AND

PDT-11

AV-JB904-A8

DC POWER HARNESS P/N 70-14978
The

Power

Harness

assembly

(Figure

has

three

con-

nectors:

@
@
@

22
10
18

The
mount

screws

pin
pin
pin

connector
connector
connector

power

supply

their

and

to
to
to

the
the
the

Terminal Controller
Video Monitor PCB,
Power Supply

and

the

Terminal

respective

nuts

chassis

Retainer

and

Rings,

Controller
are

"E"

held

clip

PCB,

connectors
place

with

fasteners.

Using Figure 2 and The Physical/Function- }

al
dc

Block
Power

Diagram
Harness

locate and identify
and connectors.

the

VIDEO MONITOR PCB
10 PIN CONNECTOR

TERMINAL CONTROLLE
R
22 PIN CONNECTOR

D.C. POWER HARNESS

POWER SUPPLY

P/N 70-14978

18 PIN CONNECTOR
MA-2975

Figure
The

Power

Power
Supply
Monitor
PCBs.
signals
from

the

which

Harness

Power

Harness

distributes

the

voltages

from

the

to
the
Terminal
Controller
and
the
Video
The
harness
also
carries
the
video
drive
are used to generate the screen presentation

Terminal

Controller

PCB

PF-10

the

Video

Monitor

PCB.

~FOR INTERNAL USE ONLY-

VT180 AND PDT-11

DIGITAL

AV-JB904-A3

TERMINAL CONTROLLER PCB P/N 54-13009

The Terminal Controller, a single 18.5 in2 PCB, 1is the

It controls the flow of
brain of the VT100 terminal.
information from the keyboard to the host computer and from
To accomplish this,
the host computer to the CRT screen.
the Terminal Controller contains the following functional
sections:

8080 Microprocessor and associated logic

8K Read Only Memory (ROM)
3K Read/Write Memory (RAM)
Keyboard Interface Logic
EIA Communications Logic
Video Processor Logic

The Terminal Controller PCB always mounts in slot 1, the
left most card slot in the card cage when viewed from the
|

rear.

Using Figure 3 and The Physical/Functional Block Diagram locate the Terminal Controller.

J2
-

3K RAM

{

OPTION

KYB.

CONN.

INTERFACE

]

[

GRAPHIC

]

EIA

.«

INTERFACE
J5

VIDEO

OPTION
CONN.

.
t

CONN.

|°©

|::

—

20 MA

OPTION

ADVANCED|: +

STP

CONNECTOR

EIA

NVR MEMORY

CONN.

EXT. VIDEO

OUT o

J6
s IO

CHARACTER

GENERATOR

VIDEO

PROCESSOR LOGIC

KEYBOARD|

MA-2976

Figure

Terminal

PF-11

Controller

-FOR

INTERNAL USE

ONLY-

VT100

DIGITAL

AND

PDT-11

AV-JB9@4-A8

The

Terminal

Controller

PCB

has

nine

connectors and each
The connection

conhector 1is used for a different function.
numbers and functions are as follows:
CONNECTOR
J1

NUMBER

FUNCTION

A
50 pin
connector
used as
the connection point for the

advanced
J2

video

type

option.

dual

in-line

1IC

used

connector

connect
the
M7071
processor
option

basic

VT104.

A
40
will

pin
connector
which.
be
used
for
future

options.
also

This

called

Terminal
J 4

connector
the

Port

1is

Standard

(STP).

A
25 pin connector
used to
connect the terminal to the
EIA

graphics
to
the

communications

connect

line.

connector

used

the

current

20mA

loop
communications
the basic VT1040.

option

to
J6

The
22
connector

PCB
edge
connect

used

the
Terminal
Controller
to
the
Power
Supply
and
the
Video
Monitor
PCB
wvia
the
dc
J7

Power

The

Harness.

phone

jack

used

connect

the

Terminal

Controller.

The

top

which

Keyboard

BNC,

allows

coax,

the

to
the

connector

customer

feed
an
external
video
source into the terminal.
J9

The

bottom

BNC,

coax,

connector
which
allows
a
customer to connect a slave
monitor
PF-12

~FOR

the

VT100.

INTERNAL

USE

ONLY-

AND PDT-11
AV-JB904-A8

VT10@0

DIGITAL

Using Figure 3 and the Physical/Functional Block Diagram locate and identify the
nine connectors on the Terminal Control|

ler.

VIDEO MONITOR PCB P/N 30-14590-02
The

the

Video Monitor PCB contains circuits which accomplish

following

functions:

Generate horizontal
and
vertical
beam deflection
signals for moving the electron beam from left to
right and from top to bottom of the screen.

Generate
and off

the

signals

beam modulation

turning on

for

the dots which make up the characters on the

screen.

Rectify the high voltages supplied from the Flyback
Transformer to control the focus and the intensity
of the information presented on the CRT screen.

When

you

stand

behind

the

unit you will

PCB mounted on the left wall of
Assembly with four stand-offs (Figure 4).
Monitor

find

the

the Video

CRT

Monitor

STANDOFFS

VIDEO MONITOR PCB

ook W

00000

[
LS
]
...............

oooooooooooooo
.................

.
.........
......
......

00000

.........

0000000

....
.......

e®

''''
'''
0%
o

'''''
[

'..

LA
8% 9@
e,

........
.......
%
e

e
e
¢

0°,0% 0%
o
e®

...................

............

........
L]
o

e
e

e
e
...........
.................. ......

'''''''''''

°
.......

oooooo
°
..

MA-2977

Figure

Video

Monitor

PF-13

PCB

-FOR

Location

INTERNAL

USE

ONLY-

DIGITAL

VT100

AND

PDT-11

AV-JB904-A8

The
from

Video

the

Monitor

Power

PCB receives

Supply

and

1ts

1its

input

drive

power

signals

(+12Vdc)
from

the

Terminal Controller via the dc Power Harness at connector
J101.
Connector J194 is used to pass signals to and from
the Flyback Transformer.
J102
provides
connections
to
the

Vertical

Coil

and

the

Vertical

bundle which
1is
soldered
to
the
signals to the CRT base connector,
CRT ground connections.
Using

Figure

and

al Block Diagram,
each Connector.

the

- Yoke.

The

wire

Video Monitor
PCB
feeds
the Horizontal Yoke, and

Physical/Function-

locate

and
|

identify

J101 FROM
POWER SUPPLY
AND

yV'4

*—lIERMHVALCONTROLLER

F101
2 AMP FUSE
CANNOT
BE

CHANGED

1102 CONNECTION TO

VERTICAL TRANSFORMER /' |104 CONNECTION TO

TO HORZ.

FLYBACK TRANSFORMER

AND VERTICAL YOKE

YOKE

WIRE BUNDLE
MA-2978

Figure

Video

Monitor

PF-14

Connectors

—-FOR

INTERNAL

USE

ONLY-

DIGITAL
'

VT100 AND PDT-11
AV-JB904-A8

The Video Monitor PCB contains a 2 amp pico-fuse Fl01l.
If the fuse fails the Video Monitor PCB will have to be
See Figure 5 for location.

replaced.

are

There

eight

adjustments

They are used to control:

the Video

Monitor

PCB.

these

The size of the screen presentation
The size of the characters
The brightness of the characters
The focus of the characters.

The

name,

adjustments

number,

are

and

called-out

1location

Physical/Function block diagram.
NAME

NUMBER

Horizontal Linearity

L102

1in

Figure

each

and

the

The adjustments are:
FUNCTION

Adjusts horizontal size of

the characters to be equal
1left
and
right
the
on
sides

Horizontal Width

L103

Adjusts

Video Centering

A1G3

Adjusts

the

screen.

horizontal

screen

size

the

horizontal

charthe
positioning of
the
within
dots
acter
raster.

Brightness

R117

Controls the brightness of

It should be
the raster.
raster
the
that
so
set
the
from
disappears
just
screen.

Focus

R122

PF-15

Adjusts sharpness
characters

-FOR

INTERNAL

USE

the

ONLY-

VT100

DIGITAL

AND

PDT-11

AV-JB904-A8

NUMBER

NAME

FUNCTION

Ver tical

Hold

AlQ1

Locks

screen

vertically

Vertical

Linearity

AlQ?2

Adjusts
the
vertical
character size to be equal
at the
top
and
bottom of
the screen.

Vertical

Height.

R110

Adjusts

vertical

screen

size

Using
al

Figure

Block

Monitor

and

Diagram

the

Physical/Function-

Locate

each

the

Video

Adjustments.

R117
BRIGHTNESS

R122

FOCUS

A103
VIDEO CENTERING

A101
VERT.

HOLD

A102

VERT.

éfi

LINEARITY —

T&)

R110

P
©
[
€

[

{

VERT. HEIGHT

L102

HORZ. LINEARITY L103

HORZ. WIDTH
MA-2979

Figure

The

Video

procedures

discussed

the

Monitor

how

ADJUST/ALIGN

Adjustment

perform
module

these

Location

adjustments

(AV-JB912-A8)

are

this

USE

ONLY-

course.

PF-16

—FOR

INTERNAL

VT100 AND PDT-11

DIGITAL

AV-JB904-A8

FLYBACK TRANSFORMER P/N 30-14590-01
The Flyback Transformer

is located

above the CRT on

The function of
the horizontal cross brace (Figure 7).
the Flyback transformer is to generate all of the high
The
voltages required for the Video Monitor Assembly.

Flyback Transformer develops the high voltages from the
horizontal deflection signal which moves the electron
The voltages
beam from right to 1left on. the screen.
40@Vdc and
and
anode,
CRT
the
developed are 11.5KV for
focus,
the
control
to
32Vdc for the Video Monitor PCB
beam shaping,

and brightness of the CRT.

The Flyback Transformer receives the drive signal
The
from the Video Monitor PCB via connnector J104.

11.5KV is

wire.

connected

CRT

the

through

heavy

red

CRT ANODE CAP

FLYBACK TRANSFORMER

MA-2980

UN
N NN NN N SNy NS

Figure

WHEN

WORKING

Flyback

THE

Transformer

TERMINAL

WITH

THE %

POWER TURNED ON DO NOT TOUCH THE FLYBACK
§

TRANSFORMER OR THE ANODE CONNECTOR ON THE @
CRT.

POINTS.

11.5KV

MAY

PRESENT

THESE

.......................

PFf-17

—FOR

INTERNAL

.
USE

ONLY-

DIGITAL

VT100

AND

PDT-11

AV-JB904-A8

FIELD SERVICE REPLACEMENT CRT MONITOR ASSEMBLY P/N 70-16187
The

Field

Service

following

consists
The

the

sheet

The

Yoke

The

Vertical

The
The

Video

metal

Assembly

the

Coil

recommended

Assembly

board

flyback
CRT

characters

single

the

CRT

the

CRT

face.

The

CRT

affect
the
deal
with

move

from

the

problem

only

that

item.

electron

beam

used

The

Yoke

left

right

takes

Assembly

and

has

horizontal

and

from

two

Both
The

positioning
of
the yoke
on
the
CRT
tilting of the display presentation.
of
the
two
centering
rings
on
the

the

vertical

and

vertical

top

bottom

adjustments

the

locate

centering

tained
CRT

the

Monitor

identify the

Field

Service

which

neck
to eliminate any
The second is the use
back
of
the
yoke
to

Physical/Functional
and

of
these
adjustment
first
1involves
the

the

presentation.
These
adjustments will be performed
ADJUST/ALIGN Module (AV-JB912-A8) of the course.

Using

the video monitor PCB and convert them
This causes the electron beam inside’

video
presentation.
the
Yoke
Assembly.

gram

the monitor.

replace

face.

Monitor

the

philosophy,

be
caused
by
the
CRT,
Yoke,
or
replace the complete CRT Monitor

unit.

horizontal outputs of
to a magnetic field.
the

to
to

maintenance

transformer

generates

PCB

Transformer

problem
is
suspected
Vertical Coil you are

control

Monitor

chassis

Monitor

Flyback

Under

The

CRT

items:

CRT

The

Replacement

Block
parts

display

the

Diacon-

replacement

Assembly.

PF-18

-FOR

INTERNAL

USE

ONLY-

DIGITAL

VT100

VT100 AND PDT-11

AV-JB904-A8

KEYBOARD

The VT100

features

a detached

keyboard

assembly which

allows the operator to position the keyboard within a 1.9

meter (6 foot) arc of the monitor for the most convenient
The keyboard assembly consists of the three
operation.
remaining

®
®
®

FRUs:

the Keyboard PCB
the Speaker
the Keyboard Cable

Using Figure 8 and the Physical/Functional Block Diagram locate each FRU.

KEYBOARD
INDICATORS

SPEAKER LOCATED
UNDER KEYBOARD PCB
SPEAKER P/N 12-15050

MAIN KEYBOARD AREA

KEYBOARD PCB

P/N 70-15765
AUXILIARY

KEYPAD AREA KEYBOARD CABLE
P/N 70-14652
MA-2981

Figure 8.

VT100 Keyboard

PF-19

-FOR

INTERNAL

USE

ONLY-

DIGITAL

VT10@

AND

PDT-11

AV-JB904-AS8

KEYBOARD PCB P/N 70-15765
The

keyboard

the

data

entry

device

for

the

terminal.

The
operator
keys
the
inputs
(data)
which
are
to
be
transferred to the host computer.
The keyboard is an 83 key
switch
matrix
type
unit
with
the
main keyboard
arranged
somewhat like a standard typewriter.
To the right of the

main
keyboard
is
an
auxiliary
keypad with
an
arrangement
similar to that of an adding machine with additional keys.
Along the top center of the keyboard are seven indicators.
The
functions
of
the
different
keys
and
the
keyboard
indicators
are
covered
1in
the
OPERATION
Module (AV-JB910-A8) of the course.

AND

ACCEPTANCE

SPEAKER P/N 12-15050
The

speaker

keyclick,
volume

1is

right

the

used

margin

keyclick

generate

bell,

and

bell

the

audible

the

alarm

tones

are

The
speaker
mounts
in
the
keyboard
base
keyboard.
It
1is
connected
by
two wires
connector end of the keyboard cable.

not

tones

for

bell.

The

adjustable.

cover
under ‘the
to
the
keyboard

KEYBOARD CABLE P/N 70-14652
The
connect

keyboard
the

cable

speaker

is
the

the

Terminal

Controller.

the

Keyboard

PCB

for

wire

1is

used

a three

wire

Keyboard

powering

carries
the

bi-directional

the

keyboard

logic.

also

the keyboard back to Terminal
asked
(scanned) for data 50 or
on the line frequency to which

and

used

keyboard

and

logic.

communications
data,
LED
the Terminal

carries

the

Controller.
60 times per
the VT100 is

PF-20

cable

the

+12Vdc

keyboard

carries
requests
for
keyboard
information, and bell commands from
to

coiled

PCB

-FOR

typed

ground
The

1line.

third

indicator
Controller
data

from

The keyboard is
second depending
set.

INTERNAL

USE

ONLY-

VT100 AND PDT-11

DIGITAL

AV-JB904-A8

PRACTICE EXERCISE
Using the text of this module and the
as
Physical/Functional Block Diagram
the
of
each
match
reference material,
to
following Field Replaceable Units
its function.

your

FUNCTION

FRU NAME

POWER

Converts input dc voltages
to

SUPPLY

ac.

Provides the deflection signals

-C.

the

for

CONTROLLER PCB

four

Controls the flow of information from the keyboard to the

the

Emulates
only.

CRT.

voltages.

host computer,
computer to the

voltages

high
the

Converts input
output

TERMINAL

CRT.

the

Provides
required

Blacken the letter

response.

host

and

the

CRT

screen.

VT52
|

terminal

of
flow
the
only
Controls
host
the
to
information
computer.

Controls

the

CRT presentation

—-FOR

INTERNAL

only.

PF-21

USE

ONLY-

VT109

DIGITAL

AND

PDT-11

AV-JB904-A8

FRU

NAME

VIDEO
MONITOR

FUNCTION

Provides

characters.

PCB

Provides

the

directly
to

High

the

CRT

Provides
the
the CRT

beam.

signals

Turns

filaments

deflect

and

4.,

Voltage
Anode.

the

CRT

OFF.

KEYBOARD

Contains

PCB

processor.

the

Controls

the

tion

and

8080 micro-

flow

from

informathe

host

computer.

Generates
the
bell tones.
Is

the

data

keyclick

entry

function.

the

match
These

Terminal

PCBs.

each

connector

connectors

Controller

Blacken

the

for

terminal.

Using the text of this module
and
Physical/Functional Block Diagram
reference,

device

and
|

letter

are

to
on

Video
of

the
a
1its

either

Monitor

your

re-—

sponse.

CONNECTOR
5.

NUMBER

FUNCTION

Connection
Advanced

point

Video

for

the

Option.

Connection point for
the
20mA
current
loop
communications
option.
External

video

Connection

input.

point

for

the

INTERNAL

USE

ONLY-

Keyboard.

PF-22

-FOR

VT106 AND PDT-11

DIGITAL

AV-JB904-A8

FUNCTION

CONNECTOR NUMBER

Connection point
graphics

for

the VT105

option.

for

point

Connection

the

keyboard.

Connection point from the Power

Terminal

the

Supply

Controller.

for
Connection point
communications line.

the

EIA

for
Connection point
communications line.

the

EIA

for
point
Connection
to
Controller
Terminal

the
the

Video

Monitor.

for

point

Connection

the

Advanced Video Option.

for

the

STP

for
point
Connection
communcations line.

the

EIA

the

Connection point for
current loop option.

the

20mA

for

the

STP

Connection

point

options.

point

Connection
keyboard.

Connection
options.

PF-23

point

-FOR

INTERNAL

USE

ONLY-

DIGITAL

VT10@

AND

PDT-11

AV-JB904-A8
CONNECTOR

NUMBER

FUNCTION

Connection

point

the

Flyback

Transformer.

Connection

point

the

CRT

base.

Connection
current

Connection

graphics

10.

point

loop

the

20mA

the

M7071

point

the

point

for

the

option.

point

option.

Connection

keyboard.
Connection

Terminal Controller
from the
Power
Supply
to
the
Video
Monitor.
Connection

external

point

video

Connection
external

11.

for

the

for

the

M7071

for

the

20mA

for

the

USE

ONLY-

input.
point

video

Connection

output.

point

keybaord.
Connection

graphics

Connection

current

point

option.
point

loop

Connection

external

PF-24

option.
point

video

—FOR

input.

INTERNAL

VT100 AND PDT-11

DIGITAL

AV-JB904-A8
FUNCTION

CONNECTOR NUMBER
12.

Connection

point

Connection

point

Connection

point

video

for

the

for

the

for

the

Power

output.

Advanced Video

option.

point

Connection

the

input.

external video

external

for

Keyboard.

13.

Connection
Supply

point

and Video

Monitor.

Connection
point
for
external video output.
Connection
options.

point

Connection

external

14. J101

for

point

video

the

STP

for

the

input.

Output
Flyback

transformer.

connection

Output

connection

vertical
coil.

vyoke

Input

connection

Power

Supply

and

to
the
vertical

point

from

and

Terminal

the

Controller.

Input

connection

the

CRT

base.

PF-25

-FOR

INTERNAL

USE

ONLY-

DIGITAL

VT108

AND

PDT-11

AV-JB904-A8
CONNECTOR

15.

J102

NUMBER

FUNCTION

Connection

point

the

CRT

base.
Connection

Terminal
Power

point

the

and

the

Controller

Supply.

Connection

point

vertical
coil.

yoke

and

vertical

Connection

point

the

Flyback

the

Flyback

Transformer.

16.

J104

Connection

point

Transformer.

Connection

point

vertical

and

vertical

yoke

the

coil.

Connection

point

the

CRT

point

the

INTERNAL

USE

ONLY-

base.
Connection

keyboard.

PF-26

-FOR

VT100 AND PDT-11

DIGITAL
|

Check

your

Exercises

answers

Solutions

with
on

AV-JB904-A8

the

Practice

following

page.

PF-27

-FOR

INTERNAL

USE

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