JVC AV-21L91-BK Service Manual page 22

AV-21L91
AV-25L91
AV-29L91
IF CIRCUIT ADJUSTMENT
Measuring
Item
instrument
Adjustment
Remote
of VCO (CW) control unit
VCO (CW)
TOO HIGH
ABOVE REFERENCE
BELOW REFERENCE
TOO LOW
Adjustment
Remote
of DELAY control unit
POINT
Setting
(Adjustment time)
NTSC 3.58
DELAY POINT
(AGC TAKE-OVER)
OTHERS
22
Test point Adjustment part
VCO (CW)
fv
. MHz
YELLOW
DISPLAY : EXIT
DELAY POINT
(AGC TAKE-OVER)
Initial setting value
22
20
No. 51898
Description
Note:
• Under normal conditions, no adjustment is required.
1. Select 1. IF from the SERVICE MENU.
2. Select 1. VCO by pressing the 1 key on the remote control unit.
3. Receive a broadcast signal.
4. Check the characters colour of the BELOW REFERENCE displayed
to yellow.
5. Press the DISPLAY key three times to return to normal screen.
1. Receive a black and white broadcast signal (colour off).
2. Select 1. IF from the SERVICE MENU.
3. Select 2. DELAY POINT by pressing the 2 key on the remote con-
trol unit.
4. Adjust the MENU –/+ key in order to eliminate any noise or beat
from the image. Any increase above the initial value produces noise
and any decrease below it produces beat.
5. Press the DISPLAY key three times to return to the normal screen.
6. Turn to other channels and make sure that there are no irregulari-
ties.