Rhodes Chroma Polaris

> From: listmicrocode@...
> 
> My tech is having a challenge to fix my tuning. I have 
> isolated the issue to voice 5 by referring to the service 
> manual and disabling the voices one by one to find the 
> culprit. Now that I know it's 5 all the time, I am at a loss 
> what to do next. The voice always tunes too high, each tuning 
> cycle (for the voice) a little different. Most times it's 
> around really high, around 10~15 ct to high on my tuner, and 
> if I get very luck, around 7 ct too high, but still way off 
> from the other voices. My tech has done the below, work, but 
> has not resolved the voice 5 high tuning issue. Is there 
> anything I can do on my own, or any area I can point him to 
> that would assist?

If your Polaris has socketed chips, which I think they all do, then you can swap one chip at a time between that voice and another. If the problem follows one particular chip, then replace that chip. Otherwise, there's a problem on the board. A leaky S&H capacitor is a possibility. The most likely bad chip is probably one of the 4051s in the S&H circuit. It might be worth changing Z62, too, since that factors into the tuning for all the voices.

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Ciao,               Paul D. DeRocco
Paul                mailto:pderocco@....com