IBM PC/XT (Model 5160): Part 2 (Running diagnostics)
21Stripped the computer down. Checked the power supply - seems to be okay, all voltages present.
Gave the motherboard a good clean.
Created a diagnostic ROM for the U18 BIOS socket. Re-attached the MDA card, speaker and the IBM Model 5151 monitor ... and the diagnostics ran!
https://minuszerodegrees.net/supersoft_landmark/Supersoft%20Landmark%20ROM.htm
The diagnostic ROM I'm using expects 640KB of RAM - I've only got 256KB on the motherboard. So I'll need to have a read of the manual to understand the errors it was flagging, whether they are related to the missing 384KB of RAM or not.
But progress - and the 5151 monitor works!
I will also update the BIOS ROM version to the latest, once I'm finished with the diagnostics.
Now the case is stripped I'll look at get it professionally refurbished (i.e. powder coated).
Components of this machine:
[1] Twin half-height 360KB 5¼" floppy drives
[2] Single 20MB hard drive (Tandon TM-262)
[3] MDA video card
[4] Persyst "Time Spectrum 384" multifunction card: 384KB RAM, RTC, parallel & serial ports
[5] Floppy drive controller with external floppy connector
[6] Hard drive controller
[7] IBM Model 5151 monochrome (green) screen
More videos on troubleshooting IBM PCs & compatibles:
https://www.youtube.com/playlist?list=PL5pwokf56wMLjhEgssoRyZJO1VWeQ09ij