Adjustment Procedures; Screen Voltage Coarse Adjustment; High-Voltage Coarse Adjustment - Panasonic BT-H1700BMC Service Manual

1.10 ADJUSTMENT PROCEDURES

1.10.1 SCREEN VOLTAGE COARSE ADJUSTMENT

SCREEN VOLTAGE COARSE ADJUSTMENT
Measuring Instruments
Card (Slot)
Test Points
Adjustment Points
Note: Ensure that the value of CC41 (CPU BLOCK) in the Service Menu is "000".
(1) Turn the SCREEN VR fully counterclockwise.
(2) Connect the oscilloscope across TP-47B and TP-GND.
(3) Connect the GND of high-voltage voltmeter to the braided wire.
(4) Connect the high-voltage voltmeter to the anode of the CRT and turn the
unit ON.
(5) Apply the 1080/60i component all-black signal to INPUT A.
(6) Check that the high-voltage value is 24 to 25 kV. If it is higher than 25 kV,
adjustment the VR502 so that the high-voltage value becomes to specified value.
(7) Turn the SCREEN VR slowly clockwise until the raster lights up slightly.
(8) Set the value of CC41 (CPU BLOCK) in the Service Menu from "000" to "002".
(9) Turn the SCREEN VR slowly clockwise until the voltage amplitude < A > of
the AKB pulse at TP-47G is about 25 V ± 2 V.
(10) Observe the waveforms of TP-47R and TP-47B, adjust the SCREEN VR so
that the amplitude voltage < A > of the AKB pulse become to 25V ± 2V.
(11) Apply the 1080/60i crosshatch signal to INPUT A.
(12) Adjust the FOCUS VR1 and VR2 so that the entire image is in focus.

1.10.2 HIGH-VOLTAGE COARSE ADJUSTMENT

HIGH-VOLTAGE COARSE ADJUSTMENT
Measuring Instruments
Card (Slot)
Test Points
Adjustment Points
Note: Perform the following adjustments after completing the Screen Voltage Coarse adjustment.
(1)Turn VR502 fully clockwise (the minimum position).
(2)Turn VR501 fully counterclockwise (the minimum position).
(3)Connect the high-voltage voltmeter to the anode of the CRT and turn the unit ON.
(4)Apply the 1080/60i crosshatch signal with circle pattern to INPUT A (Terminal Y on the Component/RGB Input Card).
(5)Turn VR502 slowly counterclockwise until the value of the high voltage is about 25 kV.
(6)Adjust the FOCUS VR1 and VR2 so that the entire image is in focus.
S. CORRECTION PWB
MAIN PWB
Signal generator (All-black signal, Crosshatch signal)
Oscilloscope
Component/RGB Input Card (Slot 1)
Anode of CRT
TP-47B, TP-47R, TP-47G [CRT SOCKET PWB]
TP-GND [CRT SOCKET PWB]
SCREEN VR [Bottom potentiometer on high-voltage transformer]
VR502 (High-voltage VR) [S.CORRECTION PWB]
FOCUS VR1 [Top potentiometer on high-voltage transformer]
FOCUS VR2 [Middle potentiometer on high-voltage transformer]
CC41 (AKB Setting) [Service Menu]
Signal generator (Crosshatch signal with circle pattern)
High-voltage voltmeter
Component/RGB Input Card (Slot 1)
Anode of CRT
VR502 (High-Voltage VR) [S. CORRECTION PWB]
FOCUS VR1 [Top potentiometer on high-voltage transformer]
FOCUS VR2 [Middle potentiometer on high-voltage transformer]
TP-XR
TP-G
(Top surface view of the S. CORRECTION PWB)
Front side
(V. sync)
Front side
VR502
VR501
(Max) (Min) (Min) (Max)
1 Vertical interval
V.BLK
<A>
25V ± 2V
AKB pulse
ELE-31