Philips MX3550D/37S Service Manual page 19

6-1
TUNER BOARD
TABLE OF CONTENTS
Tuner Adjustment Table .................................................................. 6-1
Block Diagram ................................................................................ 6-2
Circuit Diagram ............................................................................... 6-3
PCB Layout Top View ..................................................................... 6-4
PCB Layout Bottom View ............................................................... 6-5
Electrical Parts List ......................................................................... 6-6
TUNER ADJUSTMENT TABLE
Waverange Input frequency Input
VARICAP ALIGNMENT
FM
87.5 - 108MHz
(50kHz grid)
AM
531 - 1602kHz
(9kHz grid)
( 22S / 30S / 21R /
21H )
AM
530-1700kHz
(10kHz grid)
( 21L / 21L / 37S )
FM - IF
10.7MHz, 50mV
F
FM
continuous wave
FM - RF
A
108MHz
FM
87.5MHz mod=1kHz
∆f= ±22.5kHz
AM IF
C
450kHz
AM
∆f = ±15kHz
V = 3mV
Connect pin 29 of RF
IC 101 (AM Osc.)
with short wire to
AM AFC
ground (pin 28)
MW
3)
AM RF
1557kHz
MW
B
576kHz
∆f = ±30kHz
1650kHz
V as low as
RF
possible
MW
580kHz
Use Service Testprogram. By selecting the TUNER TEST test frequencies will be stored as preset frequencies automatically.
1) If sensitivity of frequency counter is too low adjust to max. channel separation
(input signal: stereo left 90% + 9%, adjust output on right channel to minimum)
3) For AM RF adjustments the original frame antenna has to be used!
6-1
Tuned to Adjust Output Scope/Voltmeter
108MHz 5130 6.5V ±1.2V
87.5MHz check 1.5V ±0.5V
1602KHz TC002 7.8V ± 0.2V
1 1.1V ±
531KHz T003
1700KHz TC002 8.0V ±
530KHz T003 1.1V ±
IC 101
23
T105 2
fo
short circuit
200P
to block AFC
Symmetric
108MHz
MAX
87.5MHz
IC 101
24
100nF 4
T102
f
o
symmetric
1557kHz TC001
576kHz T002
4
1650kHz TC001
f
o
symmetric
580kHz T002
2) RC network serves for damping the IF-filter while
adjusting the other one.
0.2V
0.2V
0.2V