[sdiy] Jupiter 6 experts?

[Doug Terrebonne]

I would try replacing the CEM3340 VCO that is stuck very high. It may be affecting the others. Trying swapping it with a good one (installing a socket would be helpful).

Doug 
synthparts.com
--- On Mon, 11/14/11, Eric Frampton <eric at ericframpton.com> wrote:

> From: Eric Frampton <eric at ericframpton.com>
> Subject: Re: [sdiy] Jupiter 6 experts?
> To: "SDIY" <Synth-diy at dropmix.xs4all.nl>
> Date: Monday, November 14, 2011, 3:32 PM
> Hi all -
> 
> After my unusually vague, slightly panicked initial post,
> I've narrowed the symptom down to this: the Oscillator 2's
> on all four voices on the 4-voice board aren't working
> properly.
> 
> All four of them are out of tune (one of them is out of
> audio range - I can see it on the scope, but can't hear it),
> and two of the three I can hear seem to have some sort of
> modulation even when all the mod routings are turned off.
> 
> If I change the front panel tuning while triggering those
> voices, the oscillators move smoothly together (as opposed
> to jumpy, or randomly) with the front panel controls.
> 
> If I put the unit into calibration mode and do Test 7
> (Linearity) and go down the line (test program D-1, D-2,
> etc.), all four Oscillator 1's respond perfectly, but all
> four Oscillator 2's go completely flatline on my scope.
> 
> Hitting Autotune doesn't make a difference on these
> oscillators - it works fine for the rest of them, though.
> 
> I tried swapping eproms between the two voice boards, no
> change.
> 
> All other functions on that board seem to be working fine,
> and everything on the 2-voice board is responding
> correctly.
> 
> Thoughts?
> 
> Thanks,
> Eric
> 
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