Sharp SC-103H Service Manual page 13

2. RECORD AMPLIFIER BIAS OSCILLATOR CHECK (Refer to Fig. 34)
R/P HEAD
Frequency Counter
Figure 34
Set Mode Selector Switch (SW-8) at "CASSETTE PLAY".
Set the unit at RECORD mode.
Shift R.LF. Switch (SW-4) to "A".
Connect V.T.V.M. to Test Point (R5, R6).
Adjust Semi-variable resistor (R409, R410) so that VTVM's reading becomes 50mV.
Adjust Oscillator Coil (L401) so that the frequency counter's reading becomes 53.5kHz+1.5kHz.
After checking bias frequency, re-check for the item 5.
Then shift R.I.F. switch (SW-4) to "B" and check that bias frequency becomes 52.25kHz+10%.
13