[sdiy] sh09 cv out drops again

[Roman Sowa]

Just an idea: clean the board in area of FET-CAP-OPAMP
Soldering might have evaporated all water from the flux/dust/chewinggum 
that is there, and later air humidity helped the dust conducting.

Roman

W dniu 2015-01-13 o 20:01, Carlos Portela pisze:
> Hi all,
>
> After 2 months I turn the sh09 on and the cv out/pitch drops when it
> is on VCA hold.
>
> Replaced IC2 lf13741 by CA3140, the fat capacitor, and IC1 4558 with
> TL072. the problem persist.
>
> Again removed the 2x 2sk30A GR to test them. After re-solder them the
> pitch was stable.
> I found that's (maybe) because of the heat from the iron.
> 10 min later was drooping again.
>
> Also checked the sample and hold from lfo section (last time I
> switched the sample n hold FET with the keyboard tracking FET) and
> there was a kind of portmento between the played notes...
>
> Any ideas what might be causing this? Bad Fets?
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