Read Sony HCD-GTX66 / HCD-GTX77 / HCD-GTX77BP / MHC-GTX66 / MHC-GTX77 / MHC-GTX77BP Service Manual online
29
HCD-GTX66/GTX77/GTX77BP
CD SECTION
[TEST DISC LIST]
Use the following test disc on test mode.
• CD:
• CD:
YEDS-18 (PART No. 3-702-101-01)
or
PATD-012 (PART No. 4-225-203-01)
Note:
1. CD Block is basically designed to operate without adjustment.
Therefore, check each item in order given.
2. Use YEDS-18 (3-702-101-01) unless otherwise indicated.
3. Use an oscilloscope with more than 10MW impedance.
4. Clean the object lens by an applicator with neutral detergent
3. Use an oscilloscope with more than 10MW 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.
following checks.
[S-CURVE CHECK]
Procedure :
1. Connect an oscilloscope to TP106 (FE) and TP124 (VC).
2. Turn the power on.
3. Load a disc (YEDS-18) and actuate the focus search. (In
1. Connect an oscilloscope to TP106 (FE) and TP124 (VC).
2. Turn the power on.
3. Load a disc (YEDS-18) and actuate the focus search. (In
consequence of open and close the disc tray, actuate the focus
search)
search)
4. Confirm that the oscilloscope waveform (S-curve) is
symmetrical between A and B. And confirm peak to peak level
within 3 ± 0.5 Vp-p.
within 3 ± 0.5 Vp-p.
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.
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).
MAIN
board
CN510
board
CN510
test tape
P-4-A100
(10 kHz, –10 dB)
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
forward
reverse
+
–
–
TP106(FE)
TP124(VC)
oscilloscope
BD91 board
symmetry
S-curve waveform
within 3
±
0.5Vp-p
A
B
Click on the first or last page to see other HCD-GTX66 / HCD-GTX77 / HCD-GTX77BP / MHC-GTX66 / MHC-GTX77 / MHC-GTX77BP service manuals if exist.