[sdiy] Yamaha PT-4 tuner needs tuning

[Ben Stuyts]

Hi,

I have bought an old Yamaha PT-4 tuning scope. It needs calibrating,  
so I'm looking for a service manual / calibration instructions. There  
are something like 25 pots and trim coils in there... The 12 tuning  
coils are easy to spot, and also 5 or 6 octave tuning trimmers, I  
think. But the rest???

I can't find anything about this tuner on the internet. Does anybody  
have a service manual?

Thanks,
Ben