[sdiy] Arp Omni PSU question

[Travis Thatcher]

Yeah - I found that one of the tantalum caps had shorted on the
negative rail which I figured caused those resistors to blow.

On Tue, May 19, 2015 at 11:45 AM, Terje Winther
<terje.winther at wintherstormer.no> wrote:
> The burn mark under the resistor is not because someone did some surgery: it
> is because the original resistor was blown because of a short circuit.
> You need to swap the resistor for the right value, and then you need to swap
> out the power transistors.
>
>
> Den 19. mai. 2015 kl. 04.15 skrev Travis Thatcher:
>
> 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!
>
> --
> http://www.travisthatcher.com
> http://www.soundcloud.com/thevoiceofsaturn
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>
> Terje Winther
> terje.winther at wintherstormer.no
> http://wintherstormer.no/
>
>
>
>
>



-- 
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