TUNER BOARD
TABLE OF CONTENTS
TUNER ADJUSTMENT TABLE ...................................................... 7-1
Circuit Diagram ............................................................................... 7-2
PCB Layout Top View ..................................................................... 7-3
PCB Layout Bottom View ............................................................... 7-4
7-1
7-1
TUNER ADJUSTMENT TABLE
Waverange
Input frequency
Input
Tuned to
Adjust
Output
Scope/Voltmeter
VARICAP ALIGNMENT
AM IF
AM RF
3)
108MHz
87.5MHz
check
6.5V 1.2V
1.0V 0.5V
T002
FM
87.5 - 108MHz
(50kHz grid)
1602KHz
531KHz
T005
1.1V
0.5V
FM
612kHz
576kHz
1404kHz
T006
1404kHz
VC001
AM
FM - IF
No need
to adjust
FM
10.7MHz, 50mV
continuous wave
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!
.
x
a
m
symmetric
f
o
.
x
a
m
symmetric
f
o
&
f = 30kHz
V
RF
as low as
possible
200P
short circuit
to block AFC
23
IC001
0
2
2
R
100nF
24
IC001
450kHz
Connect pin 29 of
IC001 (AM Osc.)
with short wire to
ground (pin 6)
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
AM
530-1710kHz
(10kHz grid)
FM - RF
7.8V 0.2V
108MHz
87.5MHz
MAX
mod=1kHz
&
f= 22.5kHz
106MHz
90.1MHz
610kHz
1400kHz
T006
VC002
MW
610kHz
1400kHz
( 21L / 21L / 37S )
8.0V 1HV
1.1V 0.2V
xa
M
fo
Symmetric
check
check
check
T005
VC001
L001
MAX
MAX
T001
MAX
T003
V=mV
&
