Adjustment - Sharp MD-X7H Service Manual

TUNER SECTION
fL: Low-range frequency
fH: High-renge frequency
• AM adjustment and confirmation
AM signal oscillator Frequency 400 Hz, 30%, AM modulation
Adjusting item Adjusting object
IF Adjust the indication of Set IF wafeform
T351 set to 1,620 kHz. 450 kHz to maximum.
Frequency cover fL: T302 (522 kHz)
(VT line voltage of Adjust the indication
pin 20 of IC302) of set to 522 kHz.
Tracking fL: T302 (990 kHz)
• FM mute level adjustment
FM signal oscillator Frequency 400 Hz, 22.5 kHz
Frequency Adjusting
method
98.0 MHz 28 dB
AM Loop Antenna
IF : Speaker Terminal
Frequency cover: IC302, pin 20
AM signal oscillator
Loop Antenna
Figure 15-1 AM IF
SO301
FM signal oscillator
Figure 15-2 FM Mute Level

ADJUSTMENT

Adjusting
method
fL: 1.1 ± 0.1 V
fH: 5.1 ± 1.3 V of
(Only confirmation)
Set the output of
speaker terminal
to maximum.
Adjusting
Adjusting object
object
VR351 Input: SO301
Output: Speaker
Terminal
Electronic
voltmeter
UNIT
GND
Electronic
Speaker
voltmeter
Terminal
UNIT
• TEST mode setting method
Holding down the ENTER button and TUNER (BAND) button,
turn on the power. Frequency is set in the memory (initial
setting) as shown in Table 15. Call the setting with the
PRESET button to use it for tuner circuit adjustment or
confirmation.
Preset No. Frequency
P01 87.5 MHz
P02 108.0 MHz
P03 90.0 MHz
P04 106.0 MHz
P05 98.0 MHz
Table 15 Initial setting of memory
CNP301
AM
ANTENNA
TERMINAL
SO301
FM
ANTENNA
TERMINAL
1
JK501
ANALOG
IN/OUT
Figure 15-3 ADJUSTMENT POINTS
– 15 –
Preset No.
P06
P07
P08
P09
P10
MAIN PWB
AM TRACKING
T302
FM MUTE
LEVEL
FE301
VR351
20 13
IC302
12
MD-X8H
Frequency
522 kHz
1,620 kHz
603 kHz
1,404 kHz
990 kHz
AM BAND
COVERAGE
AM IF
T351