Vintage Synth Repair

I've bought a Moog Prodigy that has been "upgraded" by the 
former 
owner, but something has gone wrong. There are a number of 
holes drilled in the backside and some connectors that don't do 
anything (there's a 5.4 voltage on one of those...?) Also, there are 
4 holes saying 'range scale1' and 'range scale2' but there's 
nothing connected to them. Presumably the modificator removed 
them?
the second osc is not functioning so it definitely needs looking 
after but there are traces of extensive modifications on the board 
like cut copper wires and diodes soldered on various places. It's 
a mess, and i don't know where to begin without schematics.
I'm sure there were schematics out there on the web, several 
years ago, but i'm unable to find them back... A lot of the old 
archives seem to have gone up into thin air since 1999...

The serial nr: 5019x (This is important, since there seem to be 
various incarnations of this synth.)
If anybody could help me witht finding these schematics, i'd be 
most grateful.