[sdiy] 2 vco auto-tune...how is this possible??

[Bob Weigel]

I'm trying to finish a Chroma Polaris II for someone.  It's tuning all 6 
according to the flashes of the LED ... but the 2nd vco pair...one is in 
tune and one is out a bit.  Actually it may be off most of an octave in 
the middle.  hmmm.  sounds real bad anyway. 

Now... I think the tuning is analyzed from the aux out which is just a 
switch from the main out from the vca.  So the two oscillators are 
combined at that point so the cpu no doubt sets one to pulse mode and 
offsets it to silence while tuning the other.   Anyway I tried swapping 
CEM3374's...and checking the tolerences of the resistors that would seem 
to be involved...checked the 4051's and all that seems irrelevant.  
Anybody got any suggestions that'll keep me from tearing the whole board 
out?  Thanks. -bob