From the archives:
I wanted to let you know that I've finally managed to repair my
Precious (Polysix). It was indeed the opto resistor, the PC-1, that
was faulty. It was suggested to me that I replace the old mysterious
PC-1 component with a VTL5C3 and change R93 from 4k7 to 1k2 (to get
the VTL5C3 working properly). I did and then the synth was as good
as new!
Appearently, the PC-1 is what stabilizes the expo-converter circuit.
If it's broken, the circuit can't manage to keep the synth in tune
as the voltages vary (which is especially noticeable during the time
the machine is warming up).
Jed
On Tue, Oct 16, 2012 at 9:04 PM, Darijo Berkes <darijo@technogenic.se>wrote:
> ∗∗
>
>
> I have a Polysix that gets out of tune all the time, and I need to
> calibrate it all the time.
> I remember I once read about this problem and that it was because of a
> broken component and now I can't find that info.
>
> So does anyone know what it could be?
>
> Cheers
> /D
>
> [Non-text portions of this message have been removed]
>
>
>
[Non-text portions of this message have been removed]