Panasonic TX-20LA70F / TX-20LA70P / TX-20LA7F / TX-20LA7P Service Manual ▷ View online
About lead free solder (PbF)
Note: Lead is listed as (Pb) in the periodic table of elements.
In the information below, Pb will refer to Lead solder, and PbF will refer to Lead Free Solder.
The Lead Free Solder used in our manufacturing process and discussed below is (Sn+Ag+Cu).
That is Tin (Sn), Silver (Ag) and Copper (Cu) although other types are available.
This model uses Pb Free solder in it’s manufacture due to environmental conservation issues. For service and repair work,
we’d suggest the use of Pb free solder as well, although Pb solder may be used.
PCBs manufactured using lead free solder will have the PbF within a leaf Symbol
stamped on the back of PCB.
Caution
•
Pb free solder has a higher melting point than standard solder. Typically the melting point is 50 ~ 70 °F (30~40°C)
higher. Please use a high temperature soldering iron and set it to 700 ± 20 °F (370 ± 10 °C).
higher. Please use a high temperature soldering iron and set it to 700 ± 20 °F (370 ± 10 °C).
•
Pb free solder will tend to splash when heated too high (about 1100 °F or 600 °C).
If you must use Pb solder, please completely remove all of the Pb free solder on the pins or solder area before
applying Pb solder. If this is not practical, be sure to heat the Pb free solder until it melts, before applying Pb solder.
If you must use Pb solder, please completely remove all of the Pb free solder on the pins or solder area before
applying Pb solder. If this is not practical, be sure to heat the Pb free solder until it melts, before applying Pb solder.
•
After applying PbF solder to double layered boards, please check the component side for excess solder which may
flow onto the opposite side. (see Fig.3)
flow onto the opposite side. (see Fig.3)
Suggested Pb free solder
There are several kinds of Pb free solder available for purchase. This product uses Sn+Ag+Cu (tin, silver, copper) solder.
However, Sn+Cu (tin, copper), Sn+Zn+Bi (tin, zinc, bismuth) solder can also be used. (see Fig.4)
However, Sn+Cu (tin, copper), Sn+Zn+Bi (tin, zinc, bismuth) solder can also be used. (see Fig.4)
Fig.3
Fig.4
5
Service Hints
How to remove the Pedestal assembly
Lay the main unit face down. (see Fig.5)
Remove the 4 fixing screws and the pedestal assembly. (see Fig.6)
How to remove the backcover
Remove the 10 fixing screws. (see Fig.7)
Fig.5
Fig.6
SCREWS
SCREWS
Fig.7
6
SCREWS
SCREWS
Chassis Board Layout
Setting Inspection
Voltage Confirmation
Board Name
Function
A-Board Main
Board
A-Board Tuner
A-Board AV2
A-Board AV2
Terminal
Key Control
Key Control
P-Board
Mains Input, Power Switch
P-Board Power
Supply
V-Board
Remote Receiver, LED IR
7
A-BOARD
V-BOARD
P-BOARD
KEY CONTROL
Confirm the following voltages:
A board
Normal mode
Test
point
Position
Voltage Description
TP025
C888
5V
±0,25V
5V
TP024
C891
8,2V
±0,5V
8V
TP031
R874
30V
±2V 30V
Standby mode
TP029
C868
+pin
3,3V
±0,2V
STBY3,3V
TP030
C864
+pin
1,8
±0,15
STBY1,8V
TP025
C888
<2V 5V
P board
Normal mode
TP842
Q843
23,8V
±1V
24V
switched
TP840
Connector
P2,
pin12
9,8V
±1
12V
TP3802
IC3802,
pin1
15V
±1V 15V
TP3800
IC3801,
pin4
4,3V
±0,3V
REG2
TP3801
IC3801,
pin21
4,5V
±0,3v
REG3
Standby mode
TP842
Q843
<10V
24V
switched
Self Check
Self-check is used to automatically check the bus lines and hexadecimal code of the TV set. To enter Self-Check mode, keep
pressing the STATUS button on the remote control and press the down (-/v) button on the TV set. To exit Self Check,
switch off the TV set at the power button.
pressing the STATUS button on the remote control and press the down (-/v) button on the TV set. To exit Self Check,
switch off the TV set at the power button.
8
E2CRC
99
OPTION 1
0F
OPTION 2
00
OPTION 3
A0
OPTION 4
11
OPTION 5
00
OPTION 6
05
OPTION 7
DD
OPTION 8
D2
OPTION 9
00
OPTION 10
20
OPTION 11
11
OPTION 12
00
OPTION 13
08
CHECK
AD
E2
O.K.
VCTP O.K.
TUN O.K.
Chassis 22
Model 04
Size
TUN O.K.
Chassis 22
Model 04
Size
20
VCTP B3
Self Check Complete
Panasonic GLP21L
TX-20LA70F
Display Ref.
No.
Description
P.C.B.
E2 IC1120
EAROM
A-Board
VCTP
IC1501
AUDIO VIDEO TEXT PROCESSOR
A-Board
TUN
TU001
TUNER
A-Board
If the CCU ports have been checked and found to be incorrect or not located then " - - " will appear in place of "O.K.".
E2CRC
C8
OPTION 1
0F
OPTION 2
00
OPTION 3
A0
OPTION 4
11
OPTION 5
00
OPTION 6
05
OPTION 7
DD
OPTION 8
52
OPTION 9
00
OPTION 10
20
OPTION 11
11
OPTION 12
00
OPTION 13
08
CHECK
2D
E2
O.K.
VCTP O.K.
TUN O.K.
Chassis 22
Model 02
Size
TUN O.K.
Chassis 22
Model 02
Size
20
VCTP B3
Self Check Complete
Panasonic GLP21L
TX-20LA70P
E2CRC
99
OPTION 1
0F
OPTION 2
00
OPTION 3
A0
OPTION 4
11
OPTION 5
00
OPTION 6
05
OPTION 7
DD
OPTION 8
D2
OPTION 9
00
OPTION 10
20
OPTION 11
11
OPTION 12
00
OPTION 13
08
CHECK
AD
E2
O.K.
VCTP O.K.
TUN O.K.
Chassis 22
Model 04
Size
TUN O.K.
Chassis 22
Model 04
Size
20
VCTP B3
Self Check Complete
Panasonic GLP21L
TX-20LA7F
E2CRC
6F
OPTION 1
0F
OPTION 2
00
OPTION 3
A0
OPTION 4
11
OPTION 5
00
OPTION 6
05
OPTION 7
DD
OPTION 8
52
OPTION 9
00
OPTION 10
20
OPTION 11
11
OPTION 12
00
OPTION 13
08
CHECK
2D
E2
O.K.
VCTP O.K.
TUN O.K.
Chassis 22
Model 05
Size
TUN O.K.
Chassis 22
Model 05
Size
20
VCTP B3
Self Check Complete
Panasonic GLP21L
TX-20LA7P
TV V2.06
E2 V04
E2 V04
TV V2.06
E2 V04
E2 V04
TV V2.06
E2 V04
E2 V04
TV V2.06
E2 V04
E2 V04
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