FL 8550 (serv.man13) - Harman Kardon Audio Service Manual (repair manual). Page 10

Connection point

Settings

      State

Adjustment Location

U1 (KA9220C)
Pin 57 (R11)
Pin 56 (R12)
See fig 3

1. Oscilloscope Probe: x 10
2. Oscilloscope setting

CH1: 20mV/division
CH2: 10mV/division

Remark: X-Y mode

Play State

Adjustment VR3

i. 

Set the frequency generator output to 1KHz and 100mv.

ii.  Press the play key and press skip key to move the pickup to halfway across the disk
       (R=35mm).
iii.  Adjustment VR3(focus gain) so that the Lissajous waveform is symmetrical

above the X axis and the Y axis.

Fig. 3

Higher gain

Optimum gain

Lower gain

FL8550

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