Vintage Simmons Drums (UK) Users Group

Hi,
I'm keen to learn where I may find circuit diagrams for this, because I 
have a problem with my power supply board I don't understand.
It has three +5v regulators, one +12v, one -12v, and one -5v. The 
instrument used to lock up after about 20 minutes, suggesting a thermal 
problem. Then the audio output failed, but I was still able to play it 
as a controller for another MIDI tone generator. I found one of the +5v 
was putting out +6.2v, and the -5v was putting out -6.2v (this without 
any load plugged into the board), so I changed them both, with no 
change, so now I'm stumped.
Maybe one of you recogize the layout from another product?
Many thanks
Paul