JVC AV-21L91-BK Service Manual page 21

ADJUSTMENTS
B1 POWER SUPPLY
Measuring
Item
instrument
Check of Signal
Generator
B1 POWER
SUPPLY
DC Voltmeter
FOCUS ADJUSTMENT
[AV-21L91-BK, AV-25L91-BK]
Measuring
Item
instrument
Adjustment
Signal
of FOCUS
generator
[AV-29L91-BK]
Measuring
Item
instrument
Adjustment
Signal
of FOCUS generator
Test point Adjustment part
B1 (pin 1)
GND (pin 5)
[CN00S
connector]
Test point Adjustment part
FOCUS VR
[In HVT]
Test point Adjustment part
FOCUS VR1,2
[In HVT]
No. 51898
Description
1. Receive a black and white signal.
2. Connect a DC voltmeter between B1 and GND
(between pins 1 and 5 of the connector CN00S).
3. Make sure that the voltage is as shown below.
AV-21L91-BK
AV-25L91-BK
AV-29L91-BK
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
Notes:
• Proceed to the following this adjustment after having completed the
adjustments of B1 POWER SUPPLY, SUB BRIGHT and SUB CONT.
• 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 VR2 (F2) so
that the horizontal lines will be clear and in fine detail.
3. Adjust the FOCUS VR1 (F1) so that the vertical lines will be clear
and in fine detail.
4. Make sure that the picture is in focus even when the screen gets
darkened.
AV-21L91
AV-25L91
AV-29L91
B1 voltage
DC 135 ± 2V
DC 134.5 ± 2V
21