Chroma PS Question

[Blandon Ray]

|||| Philip |||| wrote:

> I got a DOA Chroma on a bad trade :( The unit was sitting at a friend's for
> 3 years. I finally got to see it last week. We checked the synth and the
> problem seems to be with the power Supply. With no load (boards
> disconnected) it pumps the appropriate +12 -12 +5 -5 and +24 but with the
> boards connected, the ps's +12 and -12 outputs drop to about +5 and -5v. The
> circuit board that causes this does not seem to be sinking that much
> current. The problem seems to be that the ps is not regulating. Does anyone
> have experience with this ps?  There is only one common component shared by
> the +12 and -12v sections, an LM-358 op amp.

This might be more than you want to undertake, but there was a link posted a
while back to a complete Chroma power supply replacement mod (I don't know if
the guy who did this is still on the list):

http://www.till.com/articles/ChromaPowerSupply/index.html


blandon