[sdiy] Prophet 5 power supply news...

[Gil W.]

Hi all,

First let me thank you for your help on the power
supply voltage issues !

I got some interesting news...

Just t remind, I had a problem on which the +15v
voltage used to drop down to betweem +14.00v and
+14.50v , even with only the voice board connected to
the PS.

I found a bad 4016 chip on the voice board (was hot as
hell), and that I wasn't using any proper grounding
(my fault). I grounded the power supply, and took all 
CEM and CA chip out to prevent from damaging them...

Now, when I connect the entire synth, with no CEM and
CA chips, I get correct -15v and about +14.90v,
stable. But as soon as I play the keyboard, I can see
the +15v rail voltage droping again to about +14.50v. 
Stop playing and the voltage rises back to +14.90v.

I assume that once I put the CEM and CA back in the
voice board, the +15v will constantly drop again ??

So can we assume that simply the Polysix transformer
is not up to task ? or do you think there could be
other issues that makes it behave like that ?

Could it be that still, it is all an improper
grounding problem ?

Thanks again !

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