3) FOCUS BIAS ADJUSTMENT
A. Turn power on without loading a disc.
__B. Set Oscilloscope Vol/Div to DC200mV.
C. Connect TP1 (Vref) to GND and TP3 (F.E) to positive terminal on the oscilloscope.
D. Adjust VR1703 so that the voltage is 200mV DC on the oscilloscope.
Negative port of oscilloscope
FOCUS bias adjustment
positive port of oscilloscope