Panasonic C1381 - Page 16

ere Condition:
e AC 220V,50 Hz
e VGA and SVGA Signals
Test Points and Service Adjustment Controls:
Refer to page 15.
Test Equipment:
e Oscilloscope
e Digital Voltmeter
e Frequency Counter
e H, Frequency Detective Coil
e High Voltmeter
¢ Digital Photometer
1. Power Supply
1-1.
1-2.
B+ Voltage Output Adjustment
(See B-4 of Page 31)
a) Apply a VGA signal to the unit.
b) Apply 220V AC to the unit.
c) Connect a digital voltmeter between TP91 and
ground.
d) Turn the unit on.
e) Adjust R826 (B+ ADJ.) to 99V + 1.5V.
f) Vary the AC input voltage from 220V to 240V and
confirm the voltage is 99V + 1.5V.
g) Apply the normal AC voltage (220V AC) to the unit.
h) Confirm the voltage across C85? is 15.0V + 0.5V.
i) Confirm the voltage across C858 is 27.0V + 0.2V.
j) Confirm the voltage between D5003 anode and
cathode is 5V + 0.3V.
k) Confirm the voltage across 1C504 pin 3 and ground
is 12V + 0.5V.
1) Confirm the voltage across D558 is 20V + 1V.
Confirmation of Protection Circuit
(See A-5 of Page 31)
a) Apply a VGA signal and 220V AC to the unit.
b) Apply exterior DC voltage to D805 cathode.
c) Connect a digital voltmeter between D805 cathode
and ground.
d) Turn the AC switch on and confirm that the unit is
receiving the VGA signal.
DC voltage up to 30V and
confirm that the unit stops operating.
e) Raise the exterior
2. H-Hold Tracking Adjustment
2-1
. Preparations
(See C-3 of Page 31)
Connect a short jumper between TP501 and ground to
make horizontal frequency in a free run condition.
— 16 —
2-2. H-Hold 31 kHz Adjustment
(See C-4 of Page 31)
a) Apply a VGA signal to the unit.
b) Turn R515 (H. CENT.) to set click position.
c) Adjust R525 (H.H. LOW) until horizontal move-
ment stops.
2-3. H-Hold 35 kHz Adjustment
(See C-4 of Page 31)
a) Apply a SVGA signal to the unit.
b) Adjust R502 (H.H. HIGH) until horizontal move-
ment stops.
3. High Voltage Adjustment
(See E-5 of Page 31)
a) Apply a VGA signal with crosshatch pattern.
b) Turn R3116 (BRIGHT) and R3115 (CONTRAST)
controls fully clockwise.
c) Apply 220V AC to the unit.
d) To measure the high voltage, use a high impedance
high voitmeter, connect (—) to chassis and (+) to the
CRT anode contact.
e) Adjust R577 {(H.V. ADJ.) to set the high voltmeter
to245kV40.2kvV.
After adjusting R577 (H.V. ADJUST), cover
the control VR with UL tube and fill with
silicon rubber so the VR is not turned.
Warning:
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