Appendix C: Troubleshooting 35
MCMaster User’s Guide - Rev. B06 Kingston Technology Company
Hardware Issues
In the several years that the MicroMaster, and now, the MCMaster product line
have been in existence, we've accumulated a fair amount of experience with
what problems might arise. While no manual can cover every possible
contingency, we can cover the most frequently encountered problems here.

System Compatibility Issues

This section describes known problems with various PS/2 systems, and fixes.

Model 80 -- 20 MHz

Some early Model 80 planars do not support busmastership. Needless to say,
this creates problems for the MCMaster. IBM has issued two different ECA's
(engineering change announcements) ECA #048 and ECA #031, which cover a
specified range of planars. Customers who have any of these systems should
contact either their dealer or IBM service and have updated planars installed.
Problem 20 MHz systems can be identified in two ways:
By System Board part number: System boards FRU number (part
number) 90X7390 or 33F8415, or with no FRU number label, will have the
problem. (The FRU number is located near the rear edge of the system board
near slots 3 and 4.)
By System Serial Number: Systems with serial numbers equal to or below
the following:
Model System serial number
Systems manufactured in the U.S.
8580-111 72-6101500
8580-121 72-9015000
8580-311 72-6553500
8580-321 72-9215500
Systems manufactured in Australia.
8580-121 90-3100250
8580-321 90-3400600
Systems manufactured in Scotland
8580-M21 55-00LFVW0
8580-X21 55-00WMZ45
8580-111 55-00F6001