Editing IBM System/23 Datamaster (section)

== Common Faults ==

* '''Mostek MK36000 ROS modules''' degrade with age — primary cause of "computer halts mid-IPL" complaints. ROM-adapter replacements with re-burned firmware are a known workaround.
* '''TMS4132 stacked-die DRAMs''' — failure of either die in the package kills the byte. To bench-test, the upper die must be physically separated from the lower die.
* '''Linear PSU electrolytic failures''' — particularly on the RAM supply rails. See [[IBM System/23 Datamaster Capacitor Replacement Guide]].
* '''Keyboard 8048 firmware''' is Datamaster-specific; firmware failure makes the keyboard unrecoverable without a donor.
* '''Relabelled-IC problem''' — every IC on the Datamaster has an IBM internal part number (e.g. 4178015 = 8085, 4178629 = 8275 variant) which makes parts identification a major repair barrier. No IBM-published cross-reference table exists; the community has assembled a partial mapping.