[sdiy] Re: P5

[Oakley Sound]

Hi Harry,

Thanks for the reply.

> My (long gone) P5 tuned with the pot at 12:00 high.

Ah, thought so. It didn't seem to make much sense if this wasn't so.

> I'd check the voltage of the wiper with the pot centered.

Done that. And gone further into the auto-tune circuit too. There's a 
switching circuit that locks out the tune pot and the pitch bender when 
in auto-tune. But the voltage of this circuit does not waver with the 
pots centralised when the switches are closed again after the auto-tune 
has finished its run. There's something else common to all VCOs causing 
them to be offset when not in the tune routine. For now, it has me 
stumped.

One possibility is something that JH mentioned on the AH list many years 
ago about the S/H timing. This is different in the auto-tune routine as 
it is in normal operation. It could be that I have excessive droop [!!] 
somewhere in there. But on all VCOs... mmm, very odd.

I'm sure I'll get there. Need to get the humming transformer fixed first 
though.

Tony