Panasonic TX-26LE8A Service manual

TX-26LE8A

LH80 Chassis

ORDER NO. MTV0801657CE

LCD TV

Specifications

Power Source : Power Consumption

Average Use 102 W Standby condition 1.0 W

Display panel

Aspect Ratio 16:9 Visible screen size 576 mm (W) × 324 mm (H) (No. of pixels) 1,049,088 (1,366 (W) × 768 (H))

Sound

Speaker Full range × 2 pcs, 8 Ω Audio Output 20 W (10 W + 10 W), 10% THD Headphones M3 (3.5 mm) Jack × 1

PC signals VGA, SVGA, XGA, WVGA, WXGA

Receiving Systems / Band name SYSTEMS FUNCTIONS

C SINGLE 230 V, 50 Hz

Vertical scanning frequency 60 Hz

———————————————————————————————————————

1 PAL B, G, H 2 PAL I Reception 3 PAL D, K 4 SECAM B, G 5 SECAM D, K 6 SECAM K1 7 NTSC M (NTSC 3.58 / 4.5 MHz)

———————————————————————————————————————

8 NTSC 4.43 / 5.5 MHz Playback from 9 NTSC 4.43 / 6.0 MHz

of broadcast

transmission and

playback from

video cassette tape

recorders.

special VCR’s or DVD.

TX-26LE8A

10 NTSC 4.43 / 6.5 MHz 11 NTSC 3.58 / 5.5 MHz Playback from 12 NTSC 3.58 / 6.0 MHz 13 NTSC 3.58 / 6.5 MHz 14 SECAM I

———————————————————————————————————————

15 PAL 60 Hz / 5.5 MHz Playback from 16 PAL 60 Hz / 6.0 MHz 17 PAL 60 Hz / 6.5 MHz

Aerial - Rear VHF / UHF Operation Conditions Temperature : 0°C - 40°C

Humidity : 20% -- 80% RH (non-condensing)

Connection Terminals :

AV1 AUDIO L-R RCA PIN Type × 2 0.5 V[rms] Input VIDEO RCA PIN Type × 1 1.0 V[p-p] (75 Ω ) AV2 AUDIO L-R RCA PIN Type × 2 0.5 V[rms] Input VIDEO RCA PIN Type × 1 1.0 V[p-p] (75 Ω )

COMPONENT Y 1.0 V[p-p] (including synchronization)

PB/CB,PR/C

AV3 AUDIO L-R RCA PIN Type × 2 0.5 V[rms] Input VIDEO RCA PIN Type × 1 1.0 V[p-p] (75 Ω )

S VIDEO Mini DIN 4-pin Y: 1.0 V[p-p] (75 Ω) C: 0.286 V[p-p] (75 Ω)

Others HDMI 1/2 Input TYPE A Connectors

Audio Input for HDMI 1

PC Input HIGH-DENSITY D-SUB 15 PIN R, G, B / 0.7 V[p-p] (75 Ω)

Monitor AUDIO L-R RCA PIN Type × 2 0.5 V[rms] (high impedance) Output VIDEO RCA PIN Type × 1 1.0 V[p-p] (75Ω )

Dimensions (W × H × D) 700 mm × 504 mm × 225 mm (With TV Stand)

RCA PIN Type × 2 0.5 V[rms]

700 mm × 466 mm × 110 mm (TV only)

±0.35 V[p-p]

HD, VD / TTL LEVEL 2.0-5.0 V[rms] (high impedance)

and Special VCR’s or DVD.

special VCR’s or DVD.

Special Disc Players

Mass 12.5 kg (Net)

Design and specifications are subject to change without notice. Mass and dimensions shown are approximate.

CONTENTS

Page Page

1 Safety Precautions 4

1.1. General Guidelines

1.2. Touch-Current Check

2 Prevention of Electro Static Discharge (ESD) to

Electrostatically Sensitive (ES) Devices 3 About Lead Free Solder (PbF) 4 Self Check Function

4.1. Self Check

4 4

5 6 7

4.2. Power LED Blinking Timing Chart

4.3. LED and Remote Controller Receiver Check

5 Chassis Board

5.1. Chassis Installation

6 Location of Lead Wiring

6.1. Wire Dressing

6.2. Wire Dressing and Connections

7 Disassembly for Service

10 11

7 8

TX-26LE8A

7.1. AC Code dressing for 2-Pin 12

7.2. AC Code dressing for 3-Pin

7.3. Chassis Rail Installation

7.4. VESA and Pedesdal Bracket Installation

7.5. Pedestal Assembly Preparation

7.6. LED Panel Installation

7.7. LCD Panel Assembly Installation

7.8. Back Cover and Model Name Plate Installation

8 Service Mode Adjustment

8.1. SERVICE 1

8.2. SERVICE 2

8.3. Self Check Mode

8.4. Hotel Mode Adjustment

9 Adjustment

9.1. Voltage Chart of A Board

9.2. Voltage Chart of P board

10 Conductor Views

12 13 14 15 17 18 19

20 20 20 20

23 23

10.1. A-Board

10.2. A-Board

11 Schem atic Diagr am

11.1. Schematic Diagram Notes

11.2. A Board

11.3. G Board

11.4. K Board

11.5. P Board

11.6. SW Board

11.7. V Board

12 Parts Locat ion & Mechanica l Repla ceme nt Parts List

12.1. Parts Location

13 Packi ng Explo ded View 14 Repla ceme nt Parts List

14.1. Electrical Replacement Parts List

24 25

26 27 37 39 40 44 45

50 51

TX-26LE8A

1 Safety Precautions

1.1. General Guidelines

1. When servicing, observe the original lead dress. If a short circuit is found, replace all parts which have been overheated or

damaged by the short circuit.

2. After servicing, see to it that all the protective devices such as insulation barriers, insulation papers shields are properly

installed.

3. After servicing, make the following leakage current checks to prevent the customer from being exposed to shock hazards.

1.2. Touch-Current Check

1. Plug the AC cord directly into the AC outlet. Do not use an isolation transformer for this check.

2. Connect a measuring network for touch currents between each exposed metallic part on the set and a good earth ground such

as a water pipe as shown in Figure 1.

3. Use the Leakage Current Tester (Simpson 228 or equivalent) to measure the potential across the measuring network.

4. Check each exposed metallic part and measure the voltage at each point.

5. The potential at any point (touch current) expressed as voltage U

For AC: U

For DC: U

= 35 V (peak) and U2= 0.35 V (peak);

= 1.0 V,

and U2, do not exceed the following values:

NOTE :

The limit value of U

The limit value U

6. Should a measurement be out of the limits specified, there is a possibility of a shock hazard, and the equipment should be

repaired and rechecked before it is returned to the customer.

= 0.35 V (peak) for AC and U1= 1.0 V for DC correspond to the values 0.7 mA (peak) AC and 2.0 mA DC.

= 35 V (peak) for AC correspond to the value 70 mA (peak) AC for frequencies greater than 100 kHz.

TX-26LE8A

2 Prevention of Electro Static Discharge (ESD) to

Electrostatically Sensitive (ES) Devices

Some semiconductor (solid state) devices can be damaged easily by static electricity. Such components commonly are called Electrostatically Sensitive (ES) Devices. Examples of typical ES devices are integrated circuits and some fieldeffect transistors and semiconductor "chip" components. The following techniques should be used to help reduce the incidence of component damage caused by electro static discharge (ESD).

1. Immediately before handling any semiconductor component or semiconductor-equipped assembly, drain off any ESD on your body by touching a known earth ground. Alternatively, obtain and wear a commercially available discharging ESD wrist strap, which should be removed for potential shock reasons prior to applying power to the unit under test.

2. After removing an electrical assembly equipped with ES devices, place the assembly on a conductive surface such as aluminium foil to prevent electrostatic charge buildup or exposure of the assembly.

3. Use only a grounded-tip soldering iron to solder or unsolder ES devices.

4. Use only an anti-static solder removal device. Some solder removal devices not classified as "anti-static (ESD protected)" can generate electrical charges sufficient to damage ES devices.

5. Do not use freon-propelled chemicals. These can generate electrical charges sufficient to damage ES devices.

6. Do not remove a replacement ES device from its protective package until immediately before you are ready to install it (most replacement ES devices are packaged with leads electrically shorted together by conductive foam, aluminium foil or comparable conductive material).

7. Immediately before removing the protective material from the leads of a replacement ES device, touch the protective material to the chassis or circuit assembly into which the device will be installed.

Caution: Be sure no power is applied to the chassis or circuit, and observe all other safety precautions.

8. Minimize bodily motions when handling unpackaged replacement ES devices (otherwise harmless motion such as the brushing together of your clothes fabric or the lifting of your foot from a carpeted floor can generate static electricity (ESD) sufficient to damage an ES device).

TX-26LE8A

3 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 (PbF) used in our manufacturing process and discussed below is (Sn+Ag+Cu). Those are Tin (Sn), Silver (Ag) and Copper (Cu), although other types are available.

This model uses PbF in its manufacture due to environmental conservation issues. For service and repair work, we would suggest the use of PbF as well, although Pb may be used.

PCBs manufactured using lead-free will have the “PbF within a leaf Symbol” stamped on their back.

Caution

• PbF has a higher melting point than that of 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).

• PbF 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 PbF on the pins or solder area before applying Pb. If this is

not practical, be sure to heat the PbF until it melts, before applying Pb.

• After applying PbF to double layered boards, please check the component side for excess solder which may flow onto the opposite side (see Figure 2).

Figure 2

Suggested PbF

There are several kinds of PbF available for purchase. This product uses Sn+Ag+Cu (tin, silver, copper) solder. However, Sn+Cu (tin, copper) and Sn+Zn+Bi (tin, zinc, bismuth) solders can also be used.

Figure 3

TX-26LE8A

4 Self Check Function

4.1. Self Check

1. Self Check is used to automatically check the bus lines and hexadecimal codes of the TV set.

2. To get into the Self Check mode, press the “DOWN” button on the customer’s controls at the front of the set, at the same time pressing the “MENU” button on the remote control. The screen that will show is represented by Figure 4.

3. Press both “OFF TIMER” button on the remote control and “DOWN” key button on the control panel.

Figure 4

4.2. Power LED Blinking Timing Chart

1. Subject Information of LED blinking timing chart.

2. Contents When an abonormality has occurred in the unit, the protection circuit operates and resets to standby mode. At this time, the

defective block can be identified by the number of blinks of the Power LED on the front panel of the unit.

TX-26LE8A

4.3. LED and Remote Controller Receiver Check

1. Turn on the set using the power switch. Check that the LED on the front panel is as shown below. Green lamp lit = Receiving

2. Turn off the power supply using the remote controller and check that the LED is as shown below. Red lamp lit = Standby

5 Chassis Board

5.1. Chassis Installation

1. Fix 12 screws to ‘A-board’ and ‘P-board’. Tightening torque should be 50 Ncm to 80 Ncm (5 kgf cm to 8 kgf cm).

2. Fix connectors G1, G2 and G3 to AT G-board.

3. Fix 2 screws to the side of AV bracket assembly. Tightening torque should be 100 Ncm to 130 Ncm (10 kgf cm to 13 kgf cm).

4. Fix 1 screw to cabinet with power switch PCB bracket. Tightening torque should be 100 Ncm to 130 Ncm (10 kgf cm to 13 kgf cm).

TX-26LE8A

6 Location of Lead Wiring

6.1. Wire Dressing

6.2. Wire Dressing and Connections

CONNECTION 1 2 3 4 5 6 7 8 9 10 11 12 1 INV - P 2 2 A2~P4 3 A1~P3

4 G3~K1

5 G1~A4 6 G2~A5 7 V1~A7 8 A 3 ~ SPEAKER (L) 9 A 3 ~ SPEAKER (R)

10 P1~SW2 11 INV ~ A 6

TX-26LE8A

7 Disassembly for Service

7.1. AC Code dressing for 2-Pin

7.2. AC Code dressing for 3-Pin

7.3. Chassis Rail Installation

1. Put pedestal mounting and fix with 4 pcs screw.

2. Fix 3 pcs chassis frame and fix 6 pcs screw to bottom and top mounting.

TX-26LE8A

7.4. VESA and Pedesdal Bracket Installation

1. Stick 2 pieces of felt on each part of the VESA bracket.

2. Fix 4 screws to VESA bracket. Tightening torque should be 100 Ncm to 130 Ncm (10 kgf cm to 13 kgf cm).

3. Slot pedestal assembly and fix 4 screws to cabinet. Tightening torque should be 100 Ncm to 130 Ncm (10 kgf cm to 13 kgf cm).

= SCREW-XTB4 + 15JFJ (4 pcs)

= SCREW-XYN4 + F10FJK (4 pcs)

7.5. Pedestal Assembly Preparation

7.5.1. Pedestal Rotation Base

TX-26LE8A

7.5.2. Pedestal Stand Base

7.5.3. Pedestal Stand Cover

7.6. LED Panel Installation

1. Put PCB to LED panel and ensure hook is properly locked on the PCB.

2. Fix LED panel to cabinet with 3 screws. Tightening torgue should be 0.5 N m ~ 0.8 N m (5 to 8 kgf cm).

TX-26LE8A

= Screw - XTW3 + 10TFJ (3 pcs)

3. Fix wires at cabinet slit and make sure all wires are fully inserted to avoid contact with the pedestal metal.

TX-26LE8A

7.7. LCD Panel Assembly Installation

1. Put LCD panel to cabinet assembly.

2. Put LCD top mounting, LCD bottom mounting and LCD side mounting to cabinet assembly.

3. Fix screw into LCD top mounting, LCD side mounting and LCD bottom mounting. Tightening torque should be 100 N cm ~ 130 N cm (10 kgf cm to 13 kgf cm).

4. Stick sponges at top mounting and bottom mounting.

= SCREW - XTB4 + 15JFJ (7 pcs), = SCREW - XYN4 + F6FJ (6 pcs), = SPONGE (6 pcs)

7.8. Back Cover and Model Name Plate Installation

1. Stick model name plate at back cover with serial no.

TX-26LE8A

+ 42 hidden pages