Vintage Synth Repair

The CV is outputting more or less one volt per octave. I say more or
less, because some are off by as much as a hundredth of a volt, but
since the whole thing is not yet calibrated, that is approximately
correct. They remain constant across all three L/M/H positions of the
transpose switch. The lowest possible is displaying .4 volts, the
highest possible is 5.01 volts. This is on a quick powerup, without
letting it warm up.

I will remove the CV input jack tonight. It looks like it is a
normally closed jack, with it's center connector normally connected to
the center of the CV out jack. I will jumper these two connections to
simulate the jack being in place, so that should work for
troubleshooting. If it's being held open, that is not the normal
operating condition. Thank you for your help!

thx,
Scott S.

On Wed, Jul 8, 2009 at 9:55 AM, Malte Rogacki<gacki@...> wrote:
>
>
> At 21:09 Uhr -0500 06.07.2009, Scott S. wrote:
>
>> Still further, the CV input jack seems to have something stuck in it.
>> From my limited knowledge of CV, I think the keyboard is disconnected
>> if it is being operated by CV (not the case on this one). I don't know
>> if that could contribute to some of these symptoms, I will remove it
>> to rule that out.
>
> Did you remove it, whatever it was?
>
> Next step: Measuring the output of the CV out. We need to narrow it down to
> the section that is reponsible for the issue. Perhaps it is the DAC,
> perhaps it is the oscillator itself.
>
> The voltage change at the CV out should be 1 volt for each octave. How do
> things look at this point?
>
> --
> Malte Rogacki gacki@...
> ----------------------------------------------------------
> "Don't forget to TURN ON THE SYNTHESIZER. Often this is the reason why you
> get no sound out of it." (ARP 2600 Owner's Manual)
> ---------------------------------------------------------