JVC AV-20NX3 Service Manual page 18

AV-20NX3
ADJUSTMENTS
B1 POWER SUPPLY
Measuring
Item
instrument
Check of Signal
generator
B1 POWER
SUPPLY
DC voltmeter
FOCUS ADJUSTMENT
Measuring
Item
instrument
Adjustment Signal
of FOCUS
generator
IF CIRCUIT ADJUSTMENTS
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
(AGC
TAKE-OVER)
Setting
(Adjustment time)
DELAY POINT
(AGC TAKE-OVER)
18
Test point Adjustment part
B1 (pin 1)
GND (pin 5)
[CN00S
connector
in MAIN
PWB]
Test point Adjustment part
FOCUS VR
[In HVT]
Test point Adjustment part
VCO (CW)
fv
. MHz
YELLOW
DISPLAY : EXIT
DELAY POINT
Initial setting value
26
No. 52079
Description
1. Receive a black and white signal.
2. Connect a DC voltmeter between B1 and GND
(between pin 1 and 5 of the connector CN00S).
3. Make sure that the voltage is DC115 ± 1.5V.
Description
Notes:
• Set PICTURE MODE (VSM) to "BRIGHT".
• The final adjustment of CONVERGENCE must be done after the
FOCUS adjustment. (CONVERGENCE is changed by FOCUS ad-
justment.)
When makes difference by FOCUS adjustment, should be reconfirming
PURITY adjustment.
1. Receive a cross-hatch signal.
2. While looking at the screen centre, adjust the FOCUS VR so that
the vertical and horizontal lines will be clear and in fine detail.
3. Make sure that the picture is in focus even when the screen gets
darkened.
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 */T 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.