JVC AV-27F802 Service Manual page 29

ADJUSTMENT OF MTS CIRCUIT
Measuring
Item
instrument
MTS INPUT
LEVEL
check
MTS STEREO Signal
VCO generator
adjustment
Frequency
counter
Signal
MTS SAP
VCO generator
adjustment
Frequency
counter
MTS FILTER
check
MTS
TV audio
SEPARATION
multiplex
adjustment
signal
generator
Oscilloscope
L-Channel
signal waveform
1 cycle
Test point Adjustment part
No.2 IN LEVEL
[S2] No.3 FH MONITOR
Connector
5 pin AUDIO R No.4 STEREO VCO
2 pin GND
[S2] No.9 5FH MON.
Connector
3 pin TP_952.5 No.10 SAP VCO
2 pin GND
5 pin AUDIO_R
No.6 FILTER
No.7 LOW SEP.
[S2]
Connector
No.8 HI SEP.
4 pin AUDIO_L
5 pin AUDIO_R
2 pin GND
R-Channel
crosstalk portion
Minimum
No. 51757
Description
1. Select the No.2 IN LEVEL of the SOUND MODE.
2. Verify that the No.2 IN LEVEL is set at its initial setting value.
1. Receive a RF signal (nonmodulated sound signal) from the antenna
terminal.
2. Select the No.3 FH MONITOR of SOUND MODE, and change the
setting value from 0 to 1.
3. Connect the Frequency Counter to pin 5 of [S2] connector and GND
(Pin 2 of [S2] connector).
4. Select the No.4 STEREO VCO.
5. Set the initial setting value of the No.4 STEREO VCO with the LEFT/
RIGHT key of the remote control unit.
6. Adjust the No.4 STEREO VCO so that the frequency counter will
display 15.73kHz±0.1kHz.
7. Select the No.3 FH MONITOR of the SOUND MODE, and reset the
setting value from 1 to 0.
1. Receive a RF signal (non modulated sound signal) from the an-
tenna terminal.
2. Connect between pin 3 of [S2] connector and GND (Pin 2 of [S2]
connector) through 1MØ Resistor.
3. Select the No.9 5FH MON. of the SOUND MODE, and reset the
setting value from 0 to 1.
4. Connect the Frequency Counter to pin 5 of [S2] connector and GND
(Pin 2 of [S2] connector) .
5. Select the No.10 SAP VCO.
6. Set the initial setting value of the No.10 SAP VCO with the LEFT/
RIGHT key of the remote control unit.
7. Adjust the No.10 SAP VCO so that the frequency counter will dis-
play 78.67kHz±0.5kHz.
8. Select the No.9 5FH MON. of the SOUND MODE, and reset the
setting value from 1 to 0.
1. Select the No.6 FILTER of the SOUND MODE.
2. Verify that the No.6 FILTER is set at its initial setting value.
1. Input a stereo L signal (300Hz) from the TV audio multiplex signal
generator to the antenna terminal.
2. Connect an oscilloscope to pin 4 of [S2] connector, and display one
cycle portion of the 300Hz signal.
3. Change the connection of the oscilloscope to pin 5 of [S2] connec-
tor, and enlarge the voltage axis.
4. Select the No.7 LOW SEP. of the SOUND MODE.
5. Set the initial setting value of the No.7 LOW SEP. with the LEFT/
RIGHT key of the remote control unit.
6. Adjust the No.7 LOW SEP. so that the 300Hz signal level will be-
come minimum.
7. Change the signal to 3kHz, and connect an oscilloscope to pin 4 of
[S2] connector.
8. Adjust the No.8 HI SEP. so that the 3kHz signal level will become
minimum.
AV-27F802
29