Panasonic TC-21GX20P Schematic

Power
UHF
CATV
Audio
DVD
AV
Monitor
Colour Television
TC-21GX20P
GL1 Chassis
ORDER NO. MTV0701518CE
Specifications
Source : AC AUTO 110-240V, 50/60 Hz
Power Consumption : 58W
Aerial Impedance : 75Ω unbalanced
Coaxial type
Receiving System : 17 Systems
Receiving Channels :
2-13(U.S.A Standard)
14-69(U.S.A Standard)
1-125(U.S.A Standard)
Terminal :
Y 1.0 Vp-p, 75Ω
PB 0.7 Vp-p, 75Ω
PR 0.7 Vp-p, 75Ω
1, 2
Video In 1 Vp-p, 75Ω
Audio In Approx. 0.5V, 47kΩ
Out
Video Out 1 Vp-p, 75Ω
Audio Out Approx. 0.5V, 1kΩ
High Voltage : 27.5kV ±1.5
at zero beam current
Picture Tube : A51LYZ395X65
50.5cm (21 inches)
Measured diagonally,
90° deflection
Audio Output : 5W + 5w = 10W
Dimensions : Height : 472 mm
Width : 598 mm
Depth : 479 mm
Mass : 22.5 kg (Net Wt.)
Specifications are subject to change without notice. Mass and dimensions shown are approximate.
© 2007 Matsushita Electric Industrial Co., Ltd. All rights reserved. Unauthorized copying and distribution is a violation of law.
TC-21GX20P
CONTENTS
Page Page
1 Safety Precautions 3
1.1. General Guide Lines
1.2. Leakage Current Cold Check
1.3. Leakage Current Hot Check (Fig. 1)
1.4. X-Radiation
1.5. GL1 Chassis Block Diagram
2 Service Hints
2.1. Service Position for E-Board
2.2. Factory Mode Adjustment
2.3. Adjustment for White Balance
3
3
3
3
4
5
5
5
8
2.4. Adjustment for CRT CUT OFF
2.5. Adjustment Procedure
2.6. Adjustment
3 Conductor Views
4 Schematic Diagram
4.1. A Board
4.2. L Board
5 Parts Locations
6 Replacement Parts List
6.1. Replacement Parts List
8
9
10
13
14
16
21
24
25
26
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TC-21GX20P
1 Safety Precautions
1.1. General Guide Lines
1. It is advisable to insert an isolation transformer in the AC supply before servicing this hot chassis.
2. When servicing, observe the original lead dress, especially the lead dress in the high voltage circuits. If a short circuit is found, replace all parts which have been overheated or damaged by the short circuit.
3. After servicing, see to it that all the protective devices such as insulation barriers, insulation papers, shields and isolation R-C combinations, are properly installed.
4. When the receiver is not to be used for a long period of time, unplug the power cord from the AC cord outlet.
5. Potential, as high as 29.0kV is present when this receiver is in operation. Operation of the receiver without the rear cover involves the danger of a shock hazard from the receiver power supply. Servicing should not be attempted by anyone who is not thoroughly familiar with the precautions necessary when working on high voltage equipment. Always discharge the anode of the picture tube to the receiver chassis before handling the tube. After servicing make the following leakage current checks to prevent the customer from being exposed to shock hazards.
1.2. Leakage Current Cold Check
1. Unplug the AC cord and connec t a jumper between the two prongs on the plug.
2. Turn on the receiver’s power switch. Measure the resistance value, with an ohmmeter, between the jumper AC plug and each exposed metallic cabine t part on the receiver, such as screw heads, aerials, connectors, control shafts, etc. When the exposed metallic part has a return path to the chassis, the reading should be between 4 MΩ and 20 MΩ. When the exposed metal does not have a return path to the chassis, the reading must be infinite.
1.3. Leakage Current Hot Check (Fig. 1)
1. Plug the AC cord directly into the AC outlet. Do not use an isolatio n transformer for this check.
2. Check a 2 kΩ non-inductive resistor and an AC/DC current meter, in series with each exposed metallic part on the receiver in turn and an earth such as a water pipe.
The current from any point should not exceed 0.7 mA peak AC or 2 mA DC. In the case of a measurement being outside of these limits specified, there is a possibility of a shock hazard and the receiver should be repaired and rechecked before it is returned to the customer.
Fig. 1
1.4. X-Radiation
Warning:
The potential sources of X-Radiation in TV set are the EHT section and the picture tube. When using a picture tube test jig for service, ensure that jig is capable of handlin g 29.0kV without causing X-Radiation.
Note: It is important to use an accurate periodically calibrated high voltage meter.
1. Set the brightness to minimum.
2. Use the remocon to get into Service Mode.
3. Measure the EHT. The meter reading should indicate 27.5±1.5kV. If the meter indication is out of tolerance, immediate service and correction is required to prevent the possibility of premature component failure.
4. To prevent the possibility X-Radiation, it is essential to use the specified picture tube, if service replacement becomes necessary.
3
GL1 BLOCK DIAGRAM
Antenna
TUNER
SAW
Rear Inputs
AV 1 : V /L / R
Front Inputs
AV 2 : V / L/ R
YUV
YUV
CVBS4
CVBS2
IF
V
H
V OUT
H OUT
RGB
RGB
CRT
defl.
coil
MONITOR
OUT
SDA SCL
Audio Out
Mon Out
AUDIO
AMP
IC2302
IC601
UOC
EEPROM
IC1103
IC851
5V & 8V
IC801
T801
IC880
3.3V
PRIMARY
LIFE CCT
SPEAKER
TC-21GX20P
1.5. GL1 Chassis Block Diagram
4
2 Service Hints
2.1. Service Position for E-Board
1. Remove the back cover.
2. Stand the TV set as shown in Fig. 2.
3. Remove the A-Board from the TV set by pulling the main board out as shown in Figure 2.
TC-21GX20P
Fig. 2
2.2. Factory Mode Adjustment
1. Adjustment.
a. Set Timer ON (30 minutes)
Press remote’s RECALL & panel’s vol down key simultaneously to select service mode.
b. CHK should appear on right side of TV screen.
After few second s CHK 1 should appear on right side of TV screen.
NOTE :
To move from CHK 1 to CHK 2 mode, etc, please follow below rotation:-
c. CHK 1
Press digit key “4” to move option mode forward.
Press digit key “3” to move option backward.
The function rotation will be as follows :-
5
TC-21GX20P
d. After selecting the required option mode press Vol up / Vol down to adjust correct option. OSD will change to RED colour.
Press digit “0” to memorize data.
e. CHK2
Press digit key “2” to move forward to CHK2.
The function rotation will be as follows:-
f. Press digit key “4” to move forward from Colour ------> Sub-Colour, etc.
Press digit key “3” to move backward from Sub-Colour ------> Colour, etc.
g. Press volume up / volume down to adjust setting.
h. Press digit key “5” to make the AKB OFF (Blue OSD) - first time.
Press digit key “5” to make the AKB On (White OSD) - second time.
i. CHK3
Press digit key “2” to move forward to CHK 3.
The function rotation will be as follows:-
6
j. Press digit key “4” to move forward from V-SLOPE ------> V-SHIFT
Press digit key “3” to move backward from V-SHIFT ------> V-SLOPE
k. Press volume up / volume down to adjust required setting.
l. CHK4
Press digit key “2” to move forward to CHK 4.
The function rotation will be as follows:-
TC-21GX20P
m. Press digit key “4” to move forward from R-CUT ------> G-CUT
Press digit key “3” to move backward from G-CUT ------> R-CUT
n. After selecting the required mode, press volume up / volume down to adjust required setting.
o. Press digit key “5” to make the AKB OFF and H-Line mode - first time.
Press digit key “5” to make the AKB ON and Normal picture - second time.
p. After finish adjustment, press Power ON / OFF button on remote control to go to normal TV mode.
2. HOW TO CHANGE CHANNEL BY I2C BUS CONTROLLER
a. Short FA1 and FA2
b. Select Slave address ‘70H’, Sub-address ‘43H’ for RF AGC.
*Example:
Slave Address = 70H’, Sub-Address = 43H’
Data = 80H’ = Center
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TC-21GX20P
2.3. Adjustment for White Balance
Preparation:
1. Receive the white balance pattern and aging should have been performed over 30 minutes.
2. Set the picture menu to DYNAMIC NORMAL.
3. Degausse the CRT face.
4. Fix the CRT colour analyzer receiver unit to CRT face.
Adjustment of Low Light.
1. Adjustment Sub Bright, so that Y = 6.3 ± 1.0 nit.
2. Adjustment R-CUT OFF, so that X = 0.233 ± 0.015 nit.
3. Adjustment G-CUT OFF, so that Y = 0.235 ± 0.015 nit.
Adjustment of High Light
1. Adjustment Sub Bright, so that Y = 150 nit.
2. Adjustment R-Drive, so that X = 0.262 ± 0.010 nit.
3. Adjustment G-Drive, so that Y = 0.264 ± 0.010 nit.
2.4. Adjustment for CRT CUT OFF
Preparation:
1. Connect the oscilloscope probe to TPL5.
2. Screen VR min.
3. Set the data Sub Bright, Bright.
4. In service Mode at “Bright” dac press [5] in factory mode to enter vertical line and adjust by volume down or up button.
5. Adjust “Screen VR” until 1-H Line appears.
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2.5. Adjustment Procedure
2.5.1. +B Voltage
Item / preparation
1. Operate the TV set.
2. Set control as follows :
Brightness ........... minimum
Contrast ............... minimum
Adjustment procedure
1. Confirm the DC voltage at the indicated test points, as follows :
TPA 10 : 141 ± 1.5V
TPA 12 : 3.3 ± 0.5V
TPA 09 : 5 ± 1V
2.5.2. High Voltage
Item / preparation
1. Receive the crosshatch pattern.
2. Set to 0 Beam.
Screen VR .......... minimum
Contrast .............. minimum
Adjustment procedure
1. Connect a DC voltage meter to TPA 10 and confirm the +B voltage is 141.0 ± 1.5V.
2. Connect a high frequency voltmeter to heater and confirm that voltage reads 6.3 ± 0.24 (VRMS).
3. Normalize the brightness and contrast.
TC-21GX20P
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