Hey Richie, it's a hard one, in the end it would possibly cost much the same to buy another MP-1 if you can source one. Wow I just quickly checked evilbay, crap the prices are out there to get it to Oz... (hey DjC, have you got any good ones (since you are acquiring so many) to send our way for a decent price?) For less than that money you could ship it to MJMP to fix (which is a definite option BTW) hey if only he lived here (or you lived there LoL).
If you want I can get my tech guy to look at it, I want to get him going on ADA preamps. Obviously he's not free, but he's also a muso and a friend and won't rip you off (a charged hour of his time is reasonably elastic). He's done a bunch of (good) work for me lately and been very reasonable price-wise. Also MJMP (and I) can/will help narrow his focus, anyway is an option..