Crumar Musical Instruments User Group.

> Yeah, I triple checked. I'm supposed to be using the case ground,
> right? -17v Of course this changes if I unplug the cables that
> attach the PSU to the rest of the keyboard.

I can't remember if the case is 0v or not - don't bet on it.  I would 
expect the outside of the output jack to be at 0v, but look for the
0v connections on the power supply connector to be sure (JA4-5, JB 2-4, 
J0 2-4).  BTW, the same PSU appears to be used in both versions.

> Would you suggest that PSU is damaged, or is something attached to the
> PSU causing this problem?

It could be either.  You could have a faulty 12v regulator (note, the
pinouts of the +12v and -12v regulators are not the same) then one of
the rails might go quite high (like 17v).  OTOH, if the 5v rail got
shorted to chassis, then the -12v might measure -17v to chassos and the
+12v would measure 7v.  

So, unplug the power connectors and measure the +12v and -12v on the 
PSU board, using the PSU 0v as ground. 

If the PSU measures OK, switch off and reconnect one connector at a
time, switch on and see which board is causing the problem.  

> Strangely enough, the keyboard partially function, can load sounds
> from tape, play sounds, etc...

Most of the control sysem of the synth runs on a +5v supply, which is 
clearly working fine.  

And PLEASE WATCH OUT FOR THE MAINS!


Steve