Synth-DIY Yahoo! Groups Archives

Voice # 6 not staying in tune !!

2014-10-08 by jamieantonelli1978@yahoo.com

Voice #6 not staying in tune after full calibration multiple times with 3 different repair shops.
I'm at my wit send with this unit. It's in great condition and if I could fix this problem it would be a mint machine. Please help!

Re: [PolySix] Voice # 6 not staying in tune !!

2014-10-08 by Bob Grieb

Hi,

Looking at the schematic, demux IC31 (4051B) might be a

good place to start. Probably next I would replace buffer

op amp IC37. Also, the two tune trim pots might be worth

changing out. Consider replacing them with muti-turn trimmers

which are cheap these days and more stable.

If you still have the problem, it starts to get into components

that seem to me less likely to fail, so I would do those first.

Let us know how it goes. Also, you need to make sure the circuit

board is clean in this area, as flux could also cause drift.

Bob

From: "jamieantonelli1978@yahoo.com [PolySix]" <PolySix@yahoogroups.com>
To: PolySix@yahoogroups.com
Sent: Wednesday, October 8, 2014 1:12 PM
Subject: [PolySix] Voice # 6 not staying in tune !!

Voice #6 not staying in tune after full calibration multiple times with 3 different repair shops.
I'm at my wit send with this unit. It's in great condition and if I could fix this problem it would be a mint machine. Please help!

Re: [PolySix] Voice # 6 not staying in tune !!

2014-10-21 by jamieantonelli78@yahoo.com

Bob thank you so much for the info I have fowarded it to the tech that is working on the unit. I hope the problem can be solved.
I will let you know.