Question: Could you give us an explanation about the dip switch of C-BALANCE?
Answer: The R balance works as an N-1 and can be set with connecting the input and listening at the output.
Set the Send and Receive in the middle and the LC and HC to OFF.
When called in adjust the potentiometer until the lowest input signal is heared.
The C balance should be set to the situation that the Hybrid has the lowest influence on the bus that you listen to on the mixer.
So if you offer a testing signal to a different channel and move the fader of the Hybrid the signal at the output shouldn't change.
When this is okay you can fine adjust the R balance.
The easiest way is to use a 1khz 0dB test tone for both settings and a scope but it is also possible by listening and watching the VU meters.