IBM System/23 Datamaster: Difference between revisions
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A common cause of failure for this board and subsequently the whole computer is by having faulty capacitors in shortcircuit in the RAM power supply lines<ref name=":0" />. By simply removing them the issue is solved. In case of 4132 failure, each 4132 upper and lower packages must be separated in order to run the tests.
=== Video Subsystem ===
The video subsystem is almost copied verbatim from the Intel 8275 Datasheet. It consists in a 8275 variant plus a 8257 DMA device. The 4178629 made by Intel is the CRTC chip and it behaves slightly different from stock 8275s when activating the interrupts. This small difference makes the test 05 fail with standard 8275s without a patch on ROS 02h. Otherwise, the Datamaster's CRTC has the same pinout and accepts the same commands and parameters than the regular components.
=== Diagnostics port ===
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