Ive seen this before. i used to have a 3630 and had a look at modding it, in the end i decided it wasnt worth it... but the 80squid for the components?

First thing to do is get on to your friendly electronics supplier. From him/her get yourself 3 Burr Brown OPA4132PA quad op amps and sockets for same. A pair of THAT 2180 VCA's, a pair of THAT 2252's and sockets for that lot and what could possibly be the most important part, a 1 amp 9V a/c power supply.
http://www.recording.org/e-mag/article_81.shtml

Its hard to find prices in the UK. So i cant really help you yay or nay with the prices. Seems a lot tho for just electronic components. They are analogue and analogue can be expensive... i think?? anyone?