The first thing I would check is the tuning pot for that voice. I have a couple in my CS80 that are ∗very∗ fussy, in that moving them just a little bit causes the voices to go significantly out of tune.
Commonly, all of the tuning pots will move slightly as the synth heats up (and cools down). This usually will result in a slight change in pitch across all of the voices. But if one of the voices has a dirty or fussy pot, it might change more drastically than the others when it gets warm.
That said--it's just an educated guess. I would find out which voice is being problematic, then open up the CS50 (while it's warm) and try to adjust that trim pot on the voice card. If the pitch jumps wildly when you turn it, you've found your problem. With luck, a little bit of gentle turning back and forth will get the dust/dirt out and make it a bit more stable.
It's definitely worth your time to learn how to tune that thing regardless. It's basic maintenance, and not terribly difficult.
-Ted
--- On Sat, 6/25/11, jdelgoulet <jdelgoulet@...> wrote:
From: jdelgoulet <jdelgoulet@...>
Subject: [yamahacs80] CS50 weird tuned problem ... ?
To: yamahacs80@yahoogroups.com
Received: Saturday, June 25, 2011, 3:39 PM
HI all,
THis is my first post in this group ...
I'm the proud owner of a CS50 that causes me troubles...
When I play it everything is fine the first 60 minutes, then sometimes (yes sometimes not always), I get one voice going out of tune ....
I did a test today, and I've been able to play around 1h30 until one voice went out of tune.
I turn off the machine then switch it on again, the problem disappeared ...
Any idea where the problem might be ?
Thanks for your help !
Julien
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