PSX Crackling/Distorted Sound

[Gurm]

So I fired up my old PSX after a period of inactivity (went back to play Final Fantasy 9 and discovered that the PS2 dithers it to the point of making it look like I'm playing through a screen door!), and it started crackling and distorting the sound.

I figured one of the wires for the MOD chip (Stealth Mod, 2.7 I think although it MIGHT be 2.4, but I think it's 2.7 - it's been like 3 years since I opened up a PSX) was loose.

I opened it up, and yeah, one of the wires was loose. Only 6 of them were connected anyway, which I recall was normal at the time... but one of those 6 had come away. I soldered it back on, and the sound was ok - for about two boots.

Now it's distorted again, even though I've completely removed the MOD chip and all solder I put on the board.

This is a 9001 Dual-Shock system. Any idea where I should start in my quest to fix it? Or is it just a lost cause?

- Gurm