Archive for April, 2019

Fixing a PSone not reading discs (bad cap)

Tuesday, April 30th, 2019

So I have this PSone (PM-41 mainboard) that I modded with a onechip modchip and a multi frequency oscillator (I have another post on that) some time ago. It had always (at least since I got the unit) read discs rather slow, but I never thought of it, because I am not used to PSX (I generally dislike CD/DVD based consoles). Suddenly, not long ago, I couldn’t get it to read any discs. The console would recognize the disc, and go past the “menu”, but it would then sound strange, like it was retrying reads, until it would ultimately stop and hang. I tried trimming the laser pot with no real changes (except I could get it to not accepting discs at all), so I immediately blamed the laser. I then sourced another, working, PSone, and swapped the whole drive assembly, same results. I then blamed my modchip, and set the project aside. I then stumbled on a Facebook post regarding PSones not reading discs, where a guy suggested to replace capacitor C705, which is a 0.47uF/50V electrolytic SMD capacitor. Underneath it was some brown gook, that I usually find on leaked SMD caps on SNES and alike. Since I didn’t have a direct replacement cap, I found a 0.47uF/35V tantalum cap. Although voltage rating was off, I tried it anyway (I guess there would be no 50V in the PSone :P) and lo and behold, the unit now works again. It even read discs faster, I guess because re-reads are now eliminated or at least minimized.

The tantalum capacitor soldered in
The whole shebang