IBM System/23 Datamaster: Difference between revisions

For most cases it is not necessary having the probe, as the same values that are outputted through the service port are also written in the video memory, displaying the passed tests and the errors encountered. However, as the same tests that check the video display controller are the same routines that initialize it, all the tests made before the initialization cannot be seen in the screen until passed. In case some of them failed the screen would not be initialized and therefore the results wouln't be seen. For this reason the probe is still needed.

 

The computer presents itself with a pre-Model F keyboard with 83 keys. Internally, it used the very same components than the keyboard of the IBM PC would later. The only difference between them is that the PC uses a serial interface to communicate the peripheral with the computer and the Datamaster has a parallel interface. This change also implies that the code in the 8048 micricontroller both carry is different. For this reason this was also one of the most common causes of not repairable failures.