Rhodes Chroma Polaris

Until Paul jumps in, I guess anyone can throw out ideas,so I will...
The output of each synth channel goes through a 4053 MUX to createmain out and alt out.   Did you replace those on the two offending 
voices?   Also, did you scope the signal coming out of the "tune buffer"   and also the signal at the output of the 1489 Z46?
I know that those are not specific to particular voices, but maybe ifthey are bad, some voices could be more affected than others?
Bob

      From: "klosmon klosmon@... [chromapolaris]" <chromapolaris@yahoogroups.com>
 To: chromapolaris@yahoogroups.com 
 Sent: Thursday, July 9, 2015 5:04 PM
 Subject: [chromapolaris] Polaris stubborn tuning problems
   
Currently working on a Polaris that was severely mistreated.
Replaced the membrane panels, several pots;  upgraded the ROMs; tuned & 
scaled the power supply, DAC, CPU and voice board per the service manual.

Two voices (3 and 5) will not pass tune.  Re-enabling them shows that 
Oscillator B on both voices scales sharp towards the upper part of the 
keyboard;  also, when playing the filter resonance from the keyboard, 
those two voices are out of tune with the rest.

What I've done so far:  swapped out ALL ICs on the two offending voices 
-- no change.
Swapped out all the sample/hold caps and oscillator timing caps on the 
two offending voices -- no change.
Replaced the four ICs (Z60 - 63) in the sample/hold control circuit -- 
no change.

At this point, I'm out of ideas as to why these two voices are behaving 
this way.
All memory functions, internal and external controls, and other synth 
features are working correctly on all voices.

Any suggestions?
Thanks.
~GMM


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