Pioneer CDX-M12 Service Manual page 21

12 Tracking Servo Loop Gain Adjustment-2
« Purpose:
To adjust the tracking servo loop gain to an opti-
mum value.
« Maladjustment symptoms:
Poor playability, reduced resistance to vibrati6n.
* Measuring equipment / jigs:
Oscillator, gain adjustment filter, oscilloscope
¢ Measuring point:
TEX, TEY
¢ Test disc and setting:
SONY TYPE 4 (or ABEX TCD-782) Normal mode
« Adjustment position:
VR356
REFOUT
Adjustment Procedure
1. After checking that the power is OFF, connect the
gain adjustment filter and measuring equipment as
shown in the above diagram.
. Play tune TNO 12 in normal mode.(ABEX TCD-
782:TNO19)
. Set the oscillator at 1.4kHz and adjust the output of
the oscillator to 5Vp-p.
. Adjust VR356 to make the Lissajou's figure of wave-
form symmetrical about X and Y axes respectively.
High-level
gain
: Tracking
anes X=5V/div.
=50mV/div
2ms/div.
Waveform.17
Optimum
gain
Waveform. 18
Low-level
gain
Waveform.19
23