HCD-ZT4
21
SECTION 6
ELECTRICAL ADJUSTMENTS
1. Demagnetize the record/playback head with a head demagne-
tizer.
2. Do not use a magnetized screwdriver for the adjustments.
TEST TAPE
Tape
Signal
Used for
P-4-A063
6.3 kHz, -10 dB
Azimuth Adjustment
RECORD/PLAYBACK HEAD AZIMUTH ADJUSTMENT
Procedure:
1. Mode:
Playback
set
MIC board
PHONES jack
(J702)
+
–
level meter
test tape
P-4-A063
(6.3 kHz,
−
10 dB)
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
set
test tape
P-4-A063
(6.3 kHz,
−
10 dB)
oscilloscope
V
H
waveform of oscilloscope
in phase 45
°
90
°
135
°
180
°
good
wrong
MIC board
PHONES jack
(J702)
4. After the adjustments, apply suitable locking compound to the
pats adjusted.
Screw
position
L-CH
peak
within
1 dB
Output
level
L-CH
peak
R-CH
peak
within
1 dB
Screw
position
R-CH
peak
DECK SECTION
0 dB = 0.775V
Adjustment Location: Record/Playback/Erase Head
CD SECTION
Note:
1. CD Block is basically designed to operate without adjustment. There-
fore, check each item in order given.
2. Use YEDS-18 (PART No. 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 speci
fi
ed value with the following checks.
TEST DISC LIST
Use the following test disc on electrical checks.
YEDS-18 (PART No. 3-702-101-01) or
PATD-012 (PART No. 4-225-203-01)
S-CURVE CHECK
+
–
CD board
oscilloscope
(DC range)
TP106 (FE)
TP124 (VC)
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 con-
sequence of open and close the disc tray, actuate the focus
search)
4. Con
fi
rm that the oscilloscope waveform (S-curve) is symmet-
rical between A and B. And con
fi
rm peak to peak level within
1.8 ± 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.
symmetry
S-curve waveform
within 1.8 ± 0.5 Vp-p
A
B
