Service manual

10
HCD-EH10
SECTION 5
MECHANICAL ADJUSTMENTS
SECTION 6
ELECTRICAL ADJUSTMENTS
• Precaution
1. Clean the following parts with a denatured-alcohol-moistened
swab :
record/playback head pinch roller
erase head rubber belts
capstan idlers
2. Demagnetize the record/playback head with a head
demagnetizer. (Do not bring the head magnetizer close to the
erase head.)
3. Do not use a magnetized screwdriver for the adjustments.
4. After the adjustments, appiy suitable locking compound to
the parts adjusted.
5. The adjustments should be performed with the rated power
supply voltage unless otherwise noted.
• Torque Measurement
Mode Torque Meter Meter Reading
2.0 – 8.0 mN⋅m
FWD CQ-102AS (20 – 80 g⋅cm)
(0.28 – 1.12 oz⋅inch)
FWD
0.15 – 0.6 mN⋅m
Back Tension
CQ-102C (1.5 – 6.0 g⋅cm)
(0.021 – 0.083 oz⋅inch)
5.0 – 17.7 mN⋅m
FF CQ-201AS (50 – 177 g⋅cm)
(0.7 – 2.48 oz⋅inch)
5.0 – 17.7 mN⋅m
REW CQ-201B (50 – 177 g⋅cm)
(0.7 – 2.48 oz⋅inch)
• Tape Tension Measurement
Mode Tension Meter Meter Reading
FWD CQ-403A
more than 80 g
(more than 2.82 oz)
TUNER SECTION 0 dB=1 µV
[AM (MW/LW)]
Setting:
Function : TUNER
BAND button : AM
[FM]
Setting:
Function : RADIO
RADIO BAND button: FM
•Repeat the procedures in each adjustment several times, and
the tracking adjustments should be finally done by the trimmer
capacitors.
• Remove FM antenna in FM adjustment.
AM VT VOLTAGE ADJUSTMENT
Adjustment Part Frequency Display Reading on Digital Voltmeter
L852 531 kHz 1.5 ± 0.1 V
Confirmation 1602 kHz 7.2 ± 0.5 V
AM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
L851 531 kHz
FM VT VOLTAGE ADJUSTMENT
Adjustment Part Frequency Display Reading on Digital Voltmeter
L805 87.5 MHz 1.75 ± 0.1 V
Confirmation 108 MHz 6.2 ± 0.5 V
AM RF signal
generator
30% amplitude
modulation by
400 Hz signal
60 cm
set
loop antenna A
loop antenna
B
FM RF signal
generator
1 kHz frequency
deviation by FM 75 kHz
signal
Output level:
as low as possible
+
–
level meter
MAIN board
JW148
(GND)
MAIN board
JW403
(TUNER OUT L-ch)
set
MAIN board
CNP802 pin 2
MAIN board
CNP802 pin 1
digital voltmete
r
JW821 (VT)
JW805 (GND)
10 k
Ω
MAIN board
Ver. 1.1