Tuner Board - Philips FWD792 Service Manual

7-1

TUNER BOARD

TABLE OF CONTENTS
Tuner Adjustment Table .................................................................. 7-1
Circuit Diagram .............................................................................. 7-2
PCB Layout ......................... ........................................................... 7-3
Remark: The module is not intend to be repaired on component level. Circuit Diagrams and
Printed Board drawings are published for orientation only. The whole Tuner Board
Ass'y can be orderd with 12nc: 9940 000 05366 for /37/55/98.
TUNER ADJUSTMENT TABLE
Waverange Input frequency Input
VARICAP ALIGNMENT
FM
87.5 - 108MHz
(50kHz grid)
MW
531-1602kHz
(9kHz grid)
530-1700kHz
(10kHz grid)
( 98/ 55/ 51 )
FM - RF
108MHz
FM
87.5MHz mod=1kHz
f= 22.5kHz
AM IF
450kHz
AM
f = 15kHz
V = 3mV
Connect pin 6 of
RF
IC001 (AM Osc.)
with short wire to
AM AFC
ground (pin 4)
V=mV
MW
3)
AM RF
1 4 0 4 k H z
612kHz
MW
1000kHz
600kHz
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!
7-1
Tuned to Adjust Output Scope/Voltmeter
108MHz 7.5V 1V
check
87.5MHz check 1.4V 0.2V
1602KHz 7.2V 1V
check
531KHz T005
1.1V 0.2V
1700KHz check 7.2V 1V
531KHz T005 1.1V 0.2V
106MHz
VC001
MAX MAX
90.1MHz L001
IC001 T001
24
100nF T002
MAX
f
o
symmetric
T003
1404kHz V C 0 0 1
612kHz T006
MAX
1000kHz VC001
f
o
symmetric
600kHz T006
2)
RC network serves for damping the IF-filter while
adjusting the other one.