Projects

IBM PS/2 Model 57SX and 57SLC - May 16, 2025

I acquired 9 non-working PS/2 Systems as a set, all of which had dead power supplies. I tested all 9 system boards with a good PSU to confirm all of the rest of each system still worked, but the power supplies were definitely bad. After much troubleshooting, I found the diode packages on the output side of each power supply are prone to failing short, and sometimes that will blow up the transistors as well (I even had one fail this way on the bench while it was running!). I have drawn up the board layouts for all of the components on the 3 PCBs in this model of power supply. I have since sold off 7 of the machines (keeping one of each for my collection), but am working through PSU repairs on all of them. I have repaired two so far, by replacing all electrolytic capacitors (some were leaking), the two transistors, two resistors, and the commonly failed diode packages. Units that have been repaired have been working reliably since! Feel free to reach out if you are also working on such a power supply- I have spent way too many hours with these and may be able to help. Updated 8/15/2025