– 17 –
SECTION 3
ELECTRICAL ADJUSTMENTS
FM SENS/IF Adjustment
Setting:
SOURCE button
: FMI
D-BASS switch
: OFF
FREQUENCY SELECT switch : FM 200K
Procedure:
Adjust for a maximum reading on level meter.
FEB1
87.5 MHz
Adjustment Location: See page 18.
AM SENS Adjustment
Setting:
SOURCE
n
MODE button
: AM
D-BASS switch
: OFF
FREQUENCY SELECT switch : AM 10K
CD SECTION
CD section adjustments are done automatically in this set.
TUNER SECTION
0 dB = 1
µ
V
Cautions during repair
When the tuner unit is defective, replace it by a new one because
its internal block is difficult to repair.
FM Center Adjustment
Setting:
SOURCE button
: FMI
D-BASS switch
: OFF
FREQUENCY SELECT switch : FM 200K
FM RF signal
generator
dummy
antenna
antenna
terminal
set
50
Ω
50
Ω
Carrier frequency: 97.9 MHz
Output lever
: 60 dB (1 mV)
Mode
: mono
Modulation
: 1 kHz, 75 kHz deviation (100%)
+
–
FM CENTER
OUT
(Both side
of R24.)
IC1 pin
#¶
IC1 pin
#¢
digital
voltmeter
0 dBs
–3 dBs
(fc–10)
fc
(fc+10)
(kHz)
FM RF signal
generator
dummy
antenna
50
Ω
50
Ω
4
Ω
antenna
terminal
set
SPEAKER OUT
+
–
level
meter
AM RF signal
generator
dummy
antenna
antenna
terminal
set
SPEAKER OUT
level
meter
+
–
30
Ω
4
Ω
15 pF
30 pF
Procedure:
Adjust for a maximum reading on level meter.
IFT1, 3
1,400 kHz
Adjustment Location: See page 18.
Procedure:
1. Adjust IFT4 on TU1 so that the reading on the digital voltmeter
becomes in 0
±
30 mV.
2. Output an Fcenter 10 dB signal output from FM RF signal
generator so that the speaker out terminal is –20 dBs.
3. Change the FM RF signal generator frequency and check the
deviation of the frequency on + side and – side when the speaker
out terminal drops 3 dB. (Both + side and – side is approx.
50 kHz.)
4. Re-adjust IFT4 on TU1 when the difference deviation of the
frequency does more than 10 kHz.
Adjustment Location: See page 18.
