22
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.
3. Mode: Playback
4. After the adjustments, apply suitable locking compound to
the pats adjusted.
Adjustment Location:
Playback Head (Deck A).
Record/Playback/Erase Head (Deck B).
Screw
position
L-CH
peak
within
1dB
Output
level
L-CH
peak
R-CH
peak
within
1dB
Screw
position
R-CH
peak
MAIN
board
CN510
set
test tape
P-4-A100
(10 kHz, –10 dB)
pin
3
oscilloscope
L-CH
R-CH
V
H
waveform of oscilloscope
in phase 45
°
90
°
135
°
180
°
good
wrong
pin
2
pin
1
L
R
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 10M
Ω
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:
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.)
+
–
CD board
TPO102 (FE1)
TP117 (VC)
oscilloscope
A
B
symmetry
within 2.4
±
1 Vp-p
forward
reverse
