Mixer died, any ideas

Well I was just burning a track onto a minidisk and the sound went really static and high pitched, some of the sound is just squealing, the sound is fine if you put the source straight into the amp. Apart from this being really annoying because it was right at the end of an otherwise perfect recording, I kinda like my mixer when it had good sound.
When it went bad I had just put a power supply near it. The sound on it is OK at lower volume, but when you turn the channel up to the normal volume it goes bad as described above. It only seemed to happen on one channel, but now none of the channels seem to work as I was testing it.
Any ideas what has gone bad, or has happened.
If it helps its a Gemini PMX60, 2 years old or so, just out of warrenty surprise surprise

At first I thought your cement mixer was broken, I didn't notice the catagory.

...But I'm still not sure what your talking about. To me a mixer is a device with slide controls that you can plug in various inputs and route it all to one output to record it. Is this what your having trouble with? Can you bypass it to verify the problem? Got a pic of it?

Ha, no

Yep, lots of inputs, output goes to an amp to the speakers. Slides and cross fader to mix the 2+ channels. Commonly used to mix turntables by DJs. I use mine to mix various inputs and as a preamp.
Picture attached.

The sound works fine if I bypass the mixer and put the input straight into the amp, so its definately the mixer. It still powers up fine but its real squealy.
Thanks

Now I'm really cheesed off, the place where I go to buy my sounds gear (incidentally where I bought this one) has stopped selling mixers Now how am I gunna get one for a decent price?

Aha, got it!

Ok, what was happening was that the minidisk input was on aswell as the computer input on the mixer. So when I was recording to minidisk th sound was coming from the computer into the mixer into the minidisk. But as the minidisk input was selected the sound was coming from the minidisk and back into it, so basically the minidisk was feeding sound to itself. Hence the bad sound and reverb. Anyway, by shutting the minidisk input off the sound is cleared up!

YAY! Phew!