Cd Section - Sony HCD-GNX80 Service Manual

HCD-GNX80
2. Turn the adjustment screw and check output peaks. If the peaks
do not match for L-CH and R-CH, turn the adjustment screw
so that outputs match within 1dB of peak.
within
L-CH
1dB
peak
Output
level
R-CH
peak
Screw
position
L-CH
peak
3. Mode: Playback
test tape
P-4-A100
(10 kHz, –10 dB)
pin 1
L-CH
MAIN
L
board
CN510
R
set
R-CH
pin 3
waveform of oscilloscope
in phase 45 °
good
4. After the adjustments, apply suitable locking compound to
the pats adjusted.
Adjustment Location: Playback Head (Deck A).
Record/Playback/Erase Head (Deck B).
forward
22
within
1dB
Screw
position
R-CH
peak
oscilloscope
pin 2
V H
90 ° 135 ° 180 °
wrong
reverse

CD SECTION

Note:
1. CD Block is basically designed to operate without adjustment.
Therefore, check each item in order given.
2. Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.
3. Use an oscilloscope with more than 10MΩ impedance.
4. Clean the object lens by an applicator with neutral detergent
when the signal level is low than specified value with the
following checks.
S-curve Check
Connection:
CD board
TPO102 (FE1)
TP117 (VC)
Procedure:
1. Connect an oscilloscope to test point TPO102 (FE1) and TP
117(VC) on the CD board.
2. Turn the power on.
3. Put the disc (YEDS-18) in and turned power switch on again
and actuate the focus search. (actuate the focus search when
disc table is moving in and out)
4. Check the oscilloscope waveform (S-curve) is symmetrical
between A and B. And confirm peak to peak level within
2.4 ± 1 Vp-p.
S-curve waveform
Note:
• Try to measure several times to make sure than the ratio
of A : B or B : A is more than 10 : 7.
• Take sweep time as long as possible and light up the
brightness to obtain best waveform.
Checking Location: CD board (SIDE B)
(See page 24.)
oscilloscope
+
–
symmetry
A
within 2.4 ± 1 Vp-p
B