M7015

This document is an Engineering Change Order Log (DEC-O-LOG) from Digital Equipment Corporation, specifically for the M7015 Unibus Interface for LPS11 used with the PDP-11 Family processors.

Dated from October 1972 to September 1973, it details four specific engineering changes, each addressing a problem with the M7015 interface and outlining its correction:

1. M7015-00001 (Oct-72): Corrects issues with incorrect BUS REQUESTS being generated when multiple options run simultaneously. The fix involves generating requests only from a 6-bit latch and requires etch corrections and retrofitting "B" revision boards.
2. M7015-A0002 (Jan-73): Addresses data bits being picked up incorrectly during DMA operations. The solution involves inhibiting OUT HIGH/LOW signals by disabling C01 during data bus times, along with print corrections and an etch cut. This required both in-plant and field rework of all M7015 units.
3. M7015-00003 (Mar-73): Specifies corrections to circuit schematics, primarily a documentation change.
4. M7015-B0004 (Sep-73): Resolves a problem where PDP-11 systems would hang up when running RSTS11. The extensive correction involves gating BUS C1, adding an R/C delay network, and a detailed hardware rework procedure including removing/adding capacitors and resistors, drilling holes, adding griplets, and various wire changes. This also required both in-plant and field rework.

The log includes details on code, change status, etch revisions, in-plant and field effectivity, estimated installation time (for one entry), and kit contents where applicable.