This circuit requires balance adjustments for each mode (2Q/4Q) and an overall gain adjustment.

Adjust the X balance

1. Turn the [Y LEVEL] knob fully counter-clockwise
2. Turn the [X LEVEL] knob fully clockwise
3. Connect a 200Hz 10VAC triangle wave to [X IN]
4. Adjust the [BIAS] knob to just below the point where the VCA starts to turn on. This is called the "threshold point".

Adjust the Y balance

1. Set [MODE] to [4Q]
2. Set [X IN] to ‘AC’
3. Connect a 200Hz 10VAC triangle wave to [X IN]
4. Adjust P203 for minimum output.

Adjust the gain

1. Set [MODE] to [2Q]
2. Set [Y IN] to ‘DC’
3. Turn the [X LEVEL] knob fully clockwise
4. Turn the [Y LEVEL] knob full clockwise
5. Connect 5VDC to [Y IN]
6. Adjust P204 for an output of 10VAC.