NOTE: This article applies to SOME of but not ALL Macintosh 68030 systems.
On some 68030 systems, AppleCAT II/IIx version 2.3, AppleCAT IIcx version
1.0, and AppleCAT SE/30 version 1.0 are indicating failure of all four DRAM
SIMMs in bank B despite there being NO DRAM installed in bank B. This
problem can occur on all Macintosh IIcx units, and on Macintosh IIx or
Macintosh SE/30 units that contain certain ROM (not DRAM) SIMMs. The ROM
SIMM in question has the part number 630-4339 printed on the board itself.
If the AppleCAT diagnostic is used to test units with these ROM SIMMs, it
will first indicate that all bank B DRAM should be replaced. If the
diagnostic is continued, it will indicate that the logic board should be
replaced. However, the logic board should NOT be replaced; the diagnostic
has incorrectly assumed that bank B contains DRAM.
Proper operation of the Macintosh IIx, IIcx and SE/30 can still be tested
by using the appropriate MacTest diagnostic. It can also be tested by
installing DRAM in bank B before using AppleCAT.
For complete information please contact your regional Technical Support
center.