HCD-GTR33/GTR55/GTR77
14
SECTION 5
ELECTRICAL CHECK
FM TUNE LEVEL CHECK
Procedure:
1. Turn on the set.
2. Input the following signal from signal generator to FM antenna
input directly.
Carrier frequency : A = 87.5 MHz, B = 98 MHz, C = 108 MHz
Deviation
: 75 kHz
Modulation
: 1 kHz
ANT input
: 35 dBu (EMF)
Note:
Use 75 ohm coaxial cable to connect signal generator and the set.
You cannot use video cable for checking.
Use signal generator whose output impedance is 75 ohm.
3. Set to FM tuner function and tune A, B and C signals.
4. Con
fi
rm “TUNED” is lit on the display for A, B and C signals.
When the selected station signal is received in good condition,
“TUNED” is displayed.
TUNER SECTION
Adjustment Location:
Record/Playback/Erase Head
(For African model only)
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.
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
0dB = 0.775V
3. Mode: Playback
set
test tape
P-4-A063
(6.3 kHz,
10 dB)
oscilloscope
V
H
waveform of oscilloscope
in phase 45
q
90
q
135
q
180
q
good
wrong
MIC board
PHONES jack
(J702)
4. After the adjustments, apply suitable locking compound to the
pats adjusted.
signal
generator
set
