Philips LX-3000D, Service Manual

Page: 24 / 74

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
6-1 6-1
Waverange Input frequency Input Tuned to Adjust Output Scope/Voltmeter
VARICAP ALIGNMENT
AM IF
AM RF
3)
108MHz
87.5MHz
5130
check
6.5V
±
1.2V
1.5V
±
0.5V
T102
FM
87.5 - 108MHz
(50kHz grid)
1602KHz
531KHz
TC002
T003
AM
531 - 1602kHz
(9kHz grid)
1.1V
±
0.2V
FM
576kHz 576kHz
1557kHz
T002
1557kHz TC001
MW
AM
1
4
4
FM - IF
T105 FM
10.7MHz, 50mV
continuous wave
2 F
C
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)
2)
RC network serves for damping the IF-filter while
adjusting the other one.
3) For AM RF adjustments the original frame antenna has to be used!
max.
symmetric
f
o
max.
symmetric
f
o
B
∆ f = ± 30kHz
V
RF
as low as
possible
200P
short circuit
to block AFC
23
IC 101
R220
100nF
24
IC 101
450kHz
Connect pin 29 of
IC 101 (AM Osc.)
with short wire to
ground (pin 28)
AM AFC
MW
∆ f = ± 15kHz
V
RF
= 3mV
Use Service Testprogram. By selecting the TUNER TEST test frequencies will be stored as preset frequencies automatically.
1700KHz
530KHz
TC002
T003
AM
530-1700kHz
(10kHz grid)
FM - RF
7.8V ± 0.2V
108MHz
87.5MHz
MAX
A
mod=1kHz
∆ f= ± 22.5kHz
108MHz
87.5MHz
580kHz
1650kHz
T002
TC001
MW
580kHz
1650kHz
( 22S / 30S / 21R /
21H )
( 21L / 21L / 37S )
8.0V 0.2V
±
± 1.1V 0.2V
Max
fo
Symmetric