I am working on a CS-50 that had several problems with the trimpots on the M boards. I have installed new ones and replaced them all with multiturn one's. I have almost completed the calibration procedure but hit a problem when i got to the vcf calibration. The CS-80 calibration procedure states that i should get 4.0 Volts moving the cutoff lever on the front panel and measuring at R51 or R52. The only marked resistor i can find on the M boards is R6 and R7, others only have their resistance marked. Any one know witch ones they are talking about ?
At point (FH) F1 on cs-50 i only have 0.003 - 0.12 volts so i can not get the 4.0 volts there no matter how the cutoff lever or trimpot is set. Could it be before the 330 ohm resistor ? (actually a 230 ohm one in the cs-50).
Please help, I really want to close it up and get it back to its owner. I am thinking about gathering all the calibration data and make a much clearer procedure as much of the info in the calibration manual is wrong.