Tuner Adjustment - Sanyo MCH-900F Service Manual

TUNER ADJUSTMENTS
Use a plastic screw driver for adjustments.
A
Adjust the intermediate frequency of AM and FM to
the frequency
of ceramic filter.
Supply voltage
: DC 12.OV
Phones impedance
Standard output
Function switch
PARTS LOCATION
a. AM ADJUST
-1--
Adjusting
Step
Circuit
1
I
IF
+
2
Tuning
3
coverage
3=
4
Tracking
5
32 ohm
05mW(126mV)
RADIO
~k.--. ~1 ,1
@
L2103
VCT
-3
AM/FM lF OUT(H)
vcT_l ~
-3 -
\
C2106
T@
:-;-p -
/
,,lo@ I@l ~
L2104
XF213
\
@ Pin
ENT
BAND SELECT SWITCH : AM
(
Connections
VTVM
SG Frequency Position of tuning dial
Adjustment
Input
output
Oscilloscope
Closed the output Connect sweep
terminal by sweep generator to
generator, it place
C2106 (H) & 455 kHz
Low XF213
to L2103. TP202 (G)
4 -
I
t
Connect AM SG Connect VTVM to
517kHz Low end
L2104
to Test Loop
speaker terminals
Max.
1750k Hz High end VCT -4
Connect AM SG Connect VTVM to
600 kHz
600 kHz L2103
Max.
to Test Loop speaker terminals
i
1400 kHz 1400 kHz
VCT -3
(j
Repeat adjustments
b. FM ADJUSTMENT BAND SELECT SWITCH : FM
FM Dummy antenna : 75 ohm unbalance
f
Adjusting Connections
Step
SG Frequency position of tuning dial
Adjustment
VTVM
Circuit
Input output
Oscilloscope
Connect sweep
Connect sweep
n
1 IF
generator to
generator to
10.7 MHz Low
IC201 @ (H) C2106 (H)
---
& TP202 (G)
& TP202 (G)
i
2
Connect FM SG
Tuning
Connect VTVM to
87.0 MHz
Low end
L2102
to TP201 (H) &
Max.
3
coverage
speaker terminals
TP202 (G)
i
109.0 MHz
High end VCT-2
Connect FM SG
4
Connect VTVM to
Tracking
to TP201 (H) &
98.0 MHz
98.0 MHz
VCT-1
Max.
speaker terminals
TP202 (G)
5
Repeat adjustments
)
-6-