Thank you.
My technician only had a VTL5C1, which does not exactly match the
characteristics as the VTL5C3 recommended. Can anyone suggest how a
VTL5C1 would behave in the P6 in place of the failing PC-1, and what
sort of resistor replacements may be needed. Someone suggested to use a
trimpot in place of the R93, and adjust until it scales correctly.
Thanks
/Frank
On Tue, 2013-08-13 at 17:00 -0400, backshall1 wrote:
>
> Yes, that does sound like an opto-coupler issue. It's the P1501 chip
> on the
> oscillator board. It looks like a 6-pin DIP chip, but it only has 5
> pins and
> one of those isn't connected to anything, so it really has 4 pins that
> are
> used. Current replacements are Silonex NSL32SR3 and the Vactrol Vactec
> VTL5C3, and a couple of others in the Silonex and Vactrol families.
> You'll
> have to search the message threads to see what other people have used,
> or
> check out the file "PC-1 opto replacement.txt" in the group files
> section.
>
> Too bad there are no DIP package replacements available. All of these
> parts
> are radial lead so you have to figure out which leads are the diode
> side and
> what the polarity is before installing. Also, R93 usually needs to be
> changed, and it might take some experimenting to figure out what value
> works
> best.
>
> Don Backshall
>
> _____
>
> From: PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] On
> Behalf Of
> Frank Carvalho
> Sent: Tuesday, August 13, 2013 4:43 PM
> To: PolySix@yahoogroups.com
> Subject: [PolySix] P6 scaling issue
>
> Hello
>
> I am sure this is a classic issue, but it just happened to me now, and
> I
> need some advice.
>
> My P6 has not been used for a while, and since electronic equipment
> should be turned on once in a while, I pulled it out to give it some
> time turned on. But in the meantime it has developed an issue with the
> scaling of the octaves. Every octave has become about a semitone too
> wide. All the oscillators line up fine across the entire range, but
> the
> range is just scaled wrong.
>
> I read suggestions that it may be an issue with an opto-coupler, and
> if
> that is the case, where is it located, and what modern day component
> may
> replace it?
>
> If it is something else, please give me your suggestions.
>
> And before you ask, the battery was replaced long ago, before it got
> bad.
>
> Thanks
>
> Frank Carvalho
>
> [Non-text portions of this message have been removed]
>
>
>
>
>