JVC AV-28T5BK/P Service Manual page 25

4.8 ADJUSTMENT PROCEDURE
4.8.1 CHECK ITEM
Measuring
Item
instrument
B1 VOLTAGE DC voltmeter
Remote
control unit
HIGH VOLTAGE HV voltmeter
Remote
control unit
IF VCO Remote
control unit
NU
IF SERVICE ME
1. VCO
2. DELAY POINT
4.8.2 FOCUS
Measuring
Item
instrument
FOCUS Signal
generator
Test point Adjustment part
X connector [2.V/C]
1-pin:TP-91(B1) 12.RGB BLK
5-pin:TP-E
[POWER & DEF PWB]
CRT anode [2.V/C]
12.RGB BLK
Chassis GND
[1.IF]
1.VCO
VCO(CW)
TOO HIGH
ABOVE REF
JUST REF
BELOW REF
TOO LOW
Test point Adjustment part
FOCUS VR
[In HVT]
(1) Receive the any broadcast.
(2) Select 2. V/C from the SERVICE MODE.
(3) Select < 12. RGB BLK >.
(4) Press the [FUNCTION ] key to find the cut off
screen (Black screen).
(5) Connect a DC voltmeter to 1-pin and 5-pin.
(6) Make sure that the voltage is DC143V ± 2.0V.
(7) Press the [FUNCTION ] key to return to
SERVICE MODE.
(1) Receive the any broadcast.
(2) Select 2. V/C from the SERVICE MODE.
(3) Select < 12. RGB BLK >.
(4) Press the [FUNCTION ] key to find the cut off
screen (Black screen).
(5) Connect a HV voltmeter to CRT ANODE and
chassis GND. (Ground side is connected previously)
(6) Make sure that the voltage is DC 31.0kV (+1kV/-1.5kV).
(7) Press the [FUNCTION ] key to return to
SERVICE MODE.
NOTE:
Remove the probe before removing the earth clip.
• Under normal conditions, no adjustment is required.
• It must not adjust without broadcast signal.
(1) Receive the any broadcast.
(2) Select 1.IF from the SERVICE MODE.
**** MHz
(3) Select < 1.VCO >.
(4) Check the "←" position between the ABOVE REF.
and BELOW REF.
(1) Receive the cross hatch signal.
(2) Set the ZOOM mode to FULL.
(3) While looking at the screen, adjust the FOCUS VR to
the vertical and horizontal lines will be clear and infine
detail.
(4) Make sure that the picture is in focus even when the
screen gets darkened.
Description
Description
HVT
FOCUS
SCREEN
(No.YA261)1-19