[sdiy] Arp Omni PSU question

Travis Thatcher recompas at gmail.com
Tue May 19 04:15:27 CEST 2015

I've got an Omni MK I with a power supply that has me stumped. I
replaced the 2 1000uF and 250uF caps, the 2 10uFs as well as the 1uF
tants and replaced both the lm301 and the 723 as well as all the 4001
diodes.  Still, I'm getting about 36v on the v+ and -6 on v- with the
trimmers doing very little. Someone else has already done some surgery
on this synth before me - you can see the burn marks under the 4.7k
resistors. I checked and I'm getting a healthy +- 36v out of the
transformer. The power tansistors aren't heating up - would that be
the next place to look or does anyone have any suggestions for
troubleshooting. I have a power one supply that I can stick in but was
hoping to save the original. If I go the power one route - I'm
assuming I can just wire v+, gnd and v- from the power one to the
appropriate inputs on the lower voice boards and ignore the V/gnd
sense lines?

Image of the current PSU is here: http://recompas.com/xfer/omnipsu.jpg

Thanks in advance for any help!


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