JVC LT-26C31BC Service Manual

SERVICE MANUAL

WIDE LCD PANEL TELEVISION

YA16920048

LT-26C31BC

BASIC CHASSIS

TABLE OF CONTENTS

1 PRECAUTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

2 SPECIFIC SERVICE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6

3 DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10

4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-21

5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-46

No.YA169

2004/8

SPECIFICATION

Items Contents

Dimensions (W × H × D) 70.3 cm × 56.0 cm × 2.6 cm (Included stand)

70.3 cm × 49.1 cm × 9.4 cm (TV only)

Mass 19.0 kg (Included stand)

18.3 kg (TV only)

TV RF System CCIR B/G, I, D/K, L

Colour System PAL / SECAM / NTSC 3.58 / NTSC 4.43 (NTSC:EXT only).

Stereo System A2 (B/G, D/K), NICAM (B/G, I, D/K, L)

Teletext System FLOF (Fastext), TOP, WST (World Standard System)

Receiving Frequency

Intermediate Frequency

Colour Sub Carrier Frequency

Power Input AC110V - AC240 V, 50 Hz / 60 Hz

Power Consumption 148 W [Standby: 2.8 W]

Aerial Input 75 Ω unbalanced, coaxial Screen Size Diagonal: 66 cm (H: 33.9cm × V: 56.6cm) Display Resolution Horizonal : 1280 dots × Vertical : 768 dots (W-XGA) Speaker 6.6 cm round × 2 (Oblique corn)

Audio Power Output 10 W + 10 W (Rated power output)

EXT-1 (Input/Output) 21 pin Euro connector (SCART socket)

EXT-2 (Input/Output) 21 pin Euro connector (SCART socket)

EXT-3 (Input) S-Video

EXT-4 (Input) Component video

AUDIO OUT terminal 500mV(rms), Low impedance, RCA pin jack × 2 Headphone jack 3.5 mm stereo mini jack × 1 Remote Control Unit RM-C1808 (AA/R6 dry cell battery × 2)

VHF UHF

CATV

VIF SIF

PAL

SECAM

NTSC

Video Audio

Audio (L/R)

47MHz ~ 470MHz 470MHz ~ 862MHz 116MHz ~ 172MHz / 220MHz ~ 469MHz

38.9MHz(B/G, D/K, I)

33.4MHz(5.5MHz:B/G) / 32.9MHz(6.0MHz:I) / 32.4MHz(6.5MHz:L,D/K)

4.43MHz

4.40625MHz / 4.25MHz

3.58MHz / 4.43MHz

Video input, Audio L/R inputs and RGB inputs are available. TV broadcast outputs (Video and Audio L/R) are available.

Video input, S-VIDEO (Y/C) input, Audio L/R inputs and RGB inputs are available. Video and Audio L/R outputs are available. T-V LINK functions are available.

Mini-DIN 4 pin × 1 Y: 1V (p-p), Positive (Negative sync provided), 75 Ω C: 0.286V (p-p) (Burst signal), 75 Ω 1V (p-p), Positive (Negative sync provided), 75 Ω, RCA pin jack × 1 500mV (rms), High impedance, RCA pin jack × 2

RCA pin jack × 3 Y : 1V(p-p), 75 Ω Pb / B-Y: 0.7V(p-p), 75 Ω Pr / R-Y : 0.7V(p-p), 75 Ω

Component video (Pr, Pb, Y) inputs (625p, 525p, 1125i) and Audio L/R inputs are available. 525p and 625p are progressive scanning signals. Some DVD players can output these signals. 1125i is one of the new high-definition signals.

500mV(rms) (-4dBs), High impedance, RCA pin jack × 2

Design and specifications subject to change without notice.

1-2 (No.YA169)

SECTION 1

PRECAUTION

1.1 SAFETY PRECAUTIONS

(1) The design of this product contains special hardware,

many circuits and components specially for safety purposes. For continued protection, no changes should be made to the original design unless authorized in writing by the manufacturer. Replacement parts must be identical to those used in the original circuits. Service should be performed by qualified personnel only.

(2) Alterations of the design or circuitry of the products should

not be made. Any design alterations or additions will void the manufacturer's warranty and will further relieve the manufacturer of responsibility for personal injury or property damage resulting therefrom.

(3) Many electrical and mechanical parts in the products have

special safety-related characteristics. These characteristics are often not evident from visual inspection nor can the protection afforded by them necessarily be obtained by using replacement components rated for higher voltage, wattage, etc. Replacement parts which have these special safety characteristics are identified in the parts list of Service manual. Electrical components

having such features are identified by shading on the schematics and by ( ) on the parts list in Service manual. The use of a substitute replacement which does

not have the same safety characteristics as the recommended replacement part shown in the parts list of Service manual may cause shock, fire, or other hazards.

(4) Don't short between the LIVE side ground and

ISOLATED (NEUTRAL) side ground or EARTH side ground when repairing.

Some model's power circuit is partly different in the GND. The difference of the GND is shown by the LIVE : ( ) side GND, the ISOLATED (NEUTRAL) : ( ) side GND and EARTH : ( ) side GND. Don't short between the LIVE side GND and ISOLATED (NEUTRAL) side GND or EARTH side GND and never measure the LIVE side GND and ISOLATED (NEUTRAL) side GND or EARTH side GND at the same time with a measuring apparatus (oscilloscope etc.). If above note will not be kept, a fuse or any parts will be broken.

(5) If any repair has been made to the chassis, it is

recommended that the B1 setting should be checked or adjusted (See B1 POWER SUPPLY check).

(6) The high voltage applied to the picture tube must conform

with that specified in Service manual. Excessive high voltage can cause an increase in X-Ray emission, arcing and possible component damage, therefore operation under excessive high voltage conditions should be kept to a minimum, or should be prevented. If severe arcing occurs, remove the AC power immediately and determine the cause by visual inspection (incorrect installation, cracked or melted high voltage harness, poor soldering, etc.). To maintain the proper minimum level of soft X-Ray emission, components in the high voltage circuitry including the picture tube must be the exact replacements or alternatives approved by the manufacturer of the complete product.

(7) Do not check high voltage by drawing an arc. Use a high

voltage meter or a high voltage probe with a VTVM. Discharge the picture tube before attempting meter connection, by connecting a clip lead to the ground frame

and connecting the other end of the lead through a 10kΩ

2W resistor to the anode button.

(8) When service is required, observe the original lead dress.

Extra precaution should be given to assure correct lead dress in the high voltage circuit area. Where a short circuit has occurred, those components that indicate evidence of overheating should be replaced. Always use the manufacturer's replacement components.

(9) Isolation Check (Safety for Electrical Shock Hazard)

After re-assembling the product, always perform an isolation check on the exposed metal parts of the cabinet (antenna terminals, video/audio input and output terminals, Control knobs, metal cabinet, screw heads, earphone jack, control shafts, etc.) to be sure the product is safe to operate without danger of electrical shock.

a) Dielectric Strength Test

The isolation between the AC primary circuit and all metal parts exposed to the user, particularly any exposed metal part having a return path to the chassis should withstand a voltage of 3000V AC (r.m.s.) for a period of one second. (. . . . Withstand a voltage of 1100V AC (r.m.s.) to an appliance rated up to 120V, and 3000V AC (r.m.s.) to an appliance rated 200V or more, for a period of one second.) This method of test requires a test equipment not generally found in the service trade.

b) Leakage Current Check

Plug the AC line cord directly into the AC outlet (do not use a line isolation transformer during this check.). Using a "Leakage Current Tester", measure the leakage current from each exposed metal part of the cabinet, particularly any exposed metal part having a return path to the chassis, to a known good earth ground (water pipe, etc.). Any leakage current must not exceed 0.5mA AC (r.m.s.). However, in tropical area, this must not exceed 0.2mA AC (r.m.s.).

Alternate Check Method

Plug the AC line cord directly into the AC outlet (do not use a line isolation transformer during this check.). Use

an AC voltmeter having 1000Ω per volt or more sensitivity in the following manner. Connect a 1500Ω 10W resistor paralleled by a 0.15µF AC-type capacitor

between an exposed metal part and a known good earth ground (water pipe, etc.). Measure the AC voltage across the resistor with the AC voltmeter. Move the resistor connection to each exposed metal part, particularly any exposed metal part having a return path to the chassis, and measure the AC voltage across the resistor. Now, reverse the plug in the AC outlet and repeat each measurement. Any voltage measured must not exceed 0.75V AC (r.m.s.). This corresponds to

0.5mA AC (r.m.s.). However, in tropical area, this must not exceed 0.3V AC (r.m.s.). This corresponds to 0.2mA AC (r.m.s.).

AC VOLTMETER (HAVING 1000 /V, OR MORE SENSITIVITY)

0.15 F AC-TYPE

PLACE THIS PROBE

1500 10W

GOOD EARTH GROUND

ON EACH EXPOSED ME TAL PAR T

(No.YA169)1-3

1.2 INSTALLATION

1.2.1 HEAT DISSIPATION

If the heat dissipation vent behind this unit is blocked, cooling efficiency may deteriorate and temperature inside the unit will rise. Therefore, please make sure pay attention not to block the heat dissipation vent as well as the ventilation outlet behind the unit and ensure that there is room for ventilation around it.

Distance recommendations

Avoid improper installation and never position the unit where good ventilation is impossible.

150 mm

When installing this TV, distance recommendations must be maintained between the set and the wall, as well as inside a tightly enclosed area or piece of furniture. Keep to the minimum distance guidelines shown for safe operation.

1.2.2 INSTALLATION REQUIREMENTS

To ensure safety in an emergency such as an earthquake, and to prevent accidents, ensure that measures are taken to prevent the TV dropping or falling over. Use the supplied screws to firmly attach the supplied hooks to the back of the TV, and use commercially available cord to fix the TV to rigid components such as walls and columns.

200 mm 200 mm

150 mm

50 mm

Supplied hooks

1.2.3 NOTES ON HANDLING

(1) WHEN TAKING UNIT OUT OF A PACKING CASE

When taking the unit out of a packing case, do not grasp the upper part of the unit. If you take the unit out while grasping the upper part, the LCD PANEL may be damaged because of a pressure. Instead of grasping the upper part, put your hands on the lower backside or sides of the unit.

(2) AS FOR PRESSING OR TOUCHING A SPEAKER

Be careful not to press the opening of the speaker in the lower part of the unit and around them since the decorative sheet on the surface of the openings may be deformed.

1-4 (No.YA169)

1.3 HANDLING LCD PANEL

1.3.1 PRECAUTIONS FOR TRANSPORTATION

When transporting the unit, pressure exerted on the internal LCD panel due to improper handling (such as tossing and dropping) may cause damages even when the unit is carefully packed. To prevent accidents from occurring during transportation, pay careful attention before delivery, such as through explaining the handling instructions to transporters. Ensure that the following requirements are met during transportation, as the LCD panel of this unit is made of glass and therefore fragile:

(1) USE A SPECIAL PACKING CASE FOR THE LCD PANEL

When transporting the LCD panel of the unit, use a special packing case (packing materials). A special packing case is used when a LCD panel is supplied as a service spare part.

(2) ATTACH PROTECTION SHEET TO THE FRONT

Since the front (display part) of the panel is vulnerable, attach the protection sheet to the front of the LCD panel before transportation. Protection sheet is used when a LCD panel is supplied as a service spare part.

(3) AVOID VIBRATIONS AND IMPACTS

The unit may be broken if it is toppled sideways even when properly packed. Continuous vibration may shift the gap of the panel, and the unit may not be able to display images properly. Ensure that the unit is carried by at least 2 persons and pay careful attention not to exert any vibration or impact on it.

(4) DO NOT PLACE EQUIPMENT HORIZONTALLY

Ensure that it is placed upright and not horizontally during transportation and storage as the LCD panel is very vulnerable to lateral impacts and may break. During transportation, ensure that the unit is loaded along the traveling direction of the vehicle, and avoid stacking them on one another. For storage, ensure that they are stacked in 2 layers or less even when placed upright.

1.3.2 OPTICAL FILTER (ON THE FRONT OF THE LCD PANEL)

(1) Avoid placing the unit under direct sunlight over a prolonged period of time. This may cause the optical filter to deteriorate in

quality and colour. (2) Clean the filter surface by wiping it softly and lightly with a soft and lightly fuzz cloth (such as outing flannel). (3) Do not use solvents such as benzene or thinner to wipe the filter surface. This may cause the filter to deteriorate in quality or the

coating on the surface to come off. When cleaning the filter, usually use the neutral detergent diluted with water. When cleaning

the dirty filter, use water-diluted ethanol. (4) Since the filter surface is fragile, do not scratch or hit it with hard materials. Be careful enough not to touch the front surface,

especially when taking the unit out of the packing case or during transportation.

1.3.3 PRECAUTIONS FOR REPLACEMENT OF EXTERIOR PARTS

Take note of the following when replacing exterior parts (REAR COVER, FRONT PANEL, etc.):

(1) Do not exert pressure on the front of the LCD panel (filter surface). It may cause irregular colour. (2) Pay careful attention not to scratch or stain the front of the LCD panel (filter surface) with hands. (3) When replacing exterior parts, the front (LCD panel) should be placed facing downward. Place a mat, etc. underneath to avoid

causing scratches to the front (filter surface).

(No.YA169)1-5

SECTION 2

SPECIFIC SERVICE INSTRUCTIONS

2.1 FEATURES

2.1.1 FUNCTION / CIRCUITS

• DIST (Digital Image Scaling Technology) employs an interpolation method that doubles the scanning lines to realize 1250-line flickerfree picture making it especially suitable for reproducing highresolution pictures even on large-screen displays.

• New chassis design enable use of an interactive on screen control.

• The TELETEXT SYSTEM has a built-in FASTEXT (UK system), TOP (German system) and WST (world standard system) system.

• Because this TV unit corresponds to multiplex broadcast, users can enjoy music programs and sporting events with live realism. In addition, BILINGUAL programs can be heard in their original language.

• Users can make VCR dubbing of picture and sound by controlling the AV selector to select an optional source at the EXT-2 output shown in figure.

2.1.2 21-PIN EURO CONNECTOR (SCART) : EXT-1/EXT-2

Pin No. Signal designation Matching value EXT-1 EXT-2

1 AUDIO R output 500mV(rms) (Nominal), Low impedance Used (TV OUT) Used (LINE OUT) 2 AUDIO R input 500mV(rms) (Nominal), High impedance Used (R1) Used (R2) 3 AUDIO L output 500mV(rms) (Nominal), Low impedance Used (TV OUT) Used (LINE OUT) 4 AUDIO GND Used Used 5 GND (B) Used Used 6 AUDIO L input 500mV(rms) (Nominal), High impedance Used (L1) Used (L2) 7 B input 700mV 8 FUNCTION SW

(SLOW SW)

9 GND (G) Used Used

10 SCL / T-V LINK Not used Used

11 G input 700mV 12 SDA Not used Used (SDA2) 13 GND (R) Used Used 14 GND (YS) Used Not used 15 R / C input R : 700mV

16 Ys input (FAST SW) Low : 0V-0.4V, High : 1V-3V, 75Ω Used Used

17 GND (VIDEO output) Used Used 18 GND (VIDEO input) Used Used 19 VIDEO output 1V 20 VIDEO / Y input 1V 21 COMMON GND Used Used

(P-P= Peak to Peak, B-W= Blanking to white peak)

Low : 0V-3V High : 8V-12V, High impedance

C : 300mV

(P-P)

, 75Ω Used Used

(B-W)

, 75Ω Used Used

(B-W)

, 75Ω

(B-W)

, 75Ω

(P-P)

(Negative sync), 75Ω Used (TV OUT) Used (LINE OUT) (Negative sync), 75Ω Used Used

[Pin assignment]

20 18 16 14 12 10 8 6 4 2

TV EXT-1 EXT-3

EXT-2

Used Used

(SCL2 / TV-LINK)

Used (R) Used (C2/R)

EXT-4

1-6 (No.YA169)

21 19 17 15 13 11 9 7 5 3 1

2.2 TECHNICAL INFORMATION

2.2.1 LCD PANEL

This unit uses the flat type panel LCD (Liquid Crystal Display) panel that occupies as little space as possible, instead of the conventional CRT (Cathode Ray Tube), as a display unit.

2.2.1.1 STRUCTURE

The LCD panel of the unit is constructed with the metal chassis that surrounds the panel unit and supports the LCD panel part and the backlight part to protect them. The colour filter glass and the TFT glass (thin film transistor) are inserted between the front polarizing filter and the rear polarizing filter. Liquid crystals are inserted between the colour filter glass and the TFT glass. Since the gap between the two glasses is only a

few µm, a spacer (bead) is inserted in the gap to retain the gap.

The backlight unit is placed behind the LCD panel. Since liquid crystals themselves do not emit light, the backlight as an external light source emits light to the LCD panel from behind through the diffuser. Circuit boards for controlling the LCD panel and the backlight are attached around the back part of the LCD panel unit. Since the unit has the two polarizing filter that are at right angles to each other, the unit adopts "normally black" mode, where light does not pass through the polarizing filter and the screen is black when no voltage is applied to the liquid crystals.

Diffuser supporter

Top chassis

Lower frame

Upper frame

Source board

Sield case

Inverter shield cover

Inverter board

Reflection plate

Panel ASSY

Diffuser (including board)

Lamp supporter

Fig.1 Structure of the LCD panel unit

2.2.1.2 SPECIFICATIONS

The following table shows the specifications of this unit.

Item Specifications Remarks

Maximum dimensions ( W × H × D ) 62.7cm × 38.9cm × 4.9cm

Weight 8.0kg

Effective screen size Diagonal : 66cm (H:33.9cm × V : 56.6cm) 26V type

Aspect ratio 15:9 Drive device/ system a-Si-TFT, active matrix system

Resolution Horizontally 1280 × Vertically 768 × RGB <W-XGA> 2949120 dots in total

Pixel pitch (pixel size) Horizontally:0.4425mm, Vertically:0.4425mm Displayed colour 16777216 colours 256 colours for R, G, and B Brightness 450cd/m

500cd/m2 at maximum Contrast ratio 500:1 Response time 16.7ms

View angle Vertically 170°, horizontally 170°

2.2.1.3 PIXEL FAULT

There are three pixel faults - bright fault , dark fault and flicker fault - that are respectively defined as follows.

(1) BRIGHT FAULT

In this pixel fault, a cell that should not light originally is lighting on and off. For checking this pixel fault, input ALL BLACK SCREEN and find out the cell that is lighting on and off.

(2) DARK FAULT

In this pixel fault, a cell that should light originally is not lighting or lighting with the brightness twice as brighter as originally lighting. For checking this pixel fault, input 100% of each R/G/B colour and find out the cell that is not lighting.

(3) FLICKER FAULT

In the pixel fault, a cell that should light originally or not light originally is flashing on and off. For checking this pixel fault, input ALL BLACK SCREEN signal or 100% of each RGB colour and find out the cell that is flashing on and off.

(No.YA169)1-7

2.2.2 MAIN CPU PIN FUNCTION (IC001)

Pin No. Pin Name I/O Remark

1 TCK I Test purpose 2 TMS I Test purpose 3 TDI I Test purpose 4 TDO O Test purpose 5 P2.8 I Remote control input 6 P2. 9 I Mechanical power switch detection [Pushing:L] 7 P2.10 I IP error detection [Detection:L] 8 P2.11 O IP reset

9 P2.12 I TV-LINK communication 10 P2.13 I Power ON/OFF [ON:L] 11 P2.14 I Low B protect detection [Detection:L] 12 P2.15 I Power condition check [ON:L] 13 VSS33 I GND 14 VDD33 I 3.3V 15 P4.5 O TV-LINK communication 16 A20 O Memory (Program ROM) address 17 A19 O Memory (Program ROM) address 18 A18 O Memory (Program ROM) address 19 A17 O Memory (Program ROM) address 20 VSS25 I GND 21 VDD25 I 2.5V 22 A16 O Memory (Program ROM) address 23 A8 O Memory (Program ROM) address 24 A7 O Memory (Program ROM) address 25 A9 O Memory (Program ROM) address 26 A6 O Memory (Program ROM) address 27 A5 O Memory (Program ROM) address 28 A10 O Memory (Program ROM) address 29 A11 O Memory (Program ROM) address 30 A12 O Memory (Program ROM) address 31 VSS33 I GND 32 VDD33 I 3.3V 33 A4 O Memory (Program ROM) address 34 A3 O Memory (Program ROM) address 35 A2 O Memory (Program ROM) address 36 A1 O Memory (Program ROM) address 37 A0 O Memory (Program ROM) address 38 A13 O Memory (Program ROM) address 39 RAS/A14 O Memory (Program ROM) address 40 CAS/A15 O Memory (Program ROM) address 41 VSS33 I GND 42 VDD33 I 3.3V 43 MEMCLK O Clock for memory 44 CSSDRAM O Chip select for memory 45 CLKEN O Clock enable for memory 46 CSROM O Chip select for memory 47 RD O Read for memory 48 UDQM O Control IN/OUT buffer of Memory (IC003) 49 LDQM O Control IN/OUT buffer of Memory (IC003) 50 WR O Write for memory 51 D15 I/O Data (Program ROM) 52 VSS33 I GND 53 VDD33 I 3.3V 54 D7 I/O Data (Program ROM) 55 D0 I/O Data (Program ROM) 56 D14 I/O Data (Program ROM) 57 D8 I/O Data (Program ROM) 58 D6 I/O Data (Program ROM) 59 D1 I/O Data (Program ROM) 60 VSS33 I GND 61 VDD33 I 3.3V 62 D13 I/O Data (Program ROM) 63 D9 I/O Data (Program ROM) 64 D5 I/O Data (Program ROM)

Pin No. Pin Name I/O Remark

65 D2 I/O Data (Program ROM) 66 D12 I/O Data (Program ROM) 67 D10 I/O Data (Program ROM) 68 VSS33 I GND 69 VDD33 I 3.3V 70 D4 I/O Data (Program ROM) 71 D3 I/O Data (Program ROM) 72 D11 I/O Data (Program ROM) 73 RSTIN I Reset 74 P3.0 O I 75 P3.1 I/O I

C CLOCK 0 (for memory)

C DATA 0 (for memory) 76 P3.2 I Remote control input 77 P3.3 I Clock for OSD 78 P3.4 O Tuner system switch 79 P3.5 O Tuner system switch 80 P3.6 I Teletext mode:H 81 P3.7 I Power START 82 P3.8 I Not used 83 P3.9 I Picture mute 84 VSS33 I GND 85 VDD33 I 3.3V 86 VSS25 I GND 87 VDD25 I 2.5V 88 TXD0 O Sub micro computer communication 89 RXD0 I Sub micro computer communication 90 P3.12 I Not used 91 P3.13 I/O Not used 92 P3.15 I/O Not used 93 P5.14(YS2) I Ys for EXT-2 94 P5.15 I Headphone detection [Detection:L] 95 TRIG_IN I/O Not used 96 TRIG_OUT I/O Not used 97 P6.2 I Not used 98 P6.3 O I 99 P6.4 I/O I

C bus clock for IC control

C bus data for IC control

100 P6.5 O Multi-sound process reset 101 P6.6 I/O I

C bus data for IC control

102 VSYNC O Vertical sync for OSD 103 HSYNC O Horizontal sync for OSD 104 COR/RSTOUT O Not used 105 BLANK O Ys for OSD/Teletext 106 VDD33 I 3.3V 107 VSS33 I GND 108 XTAL1 I 6MHz 109 XTAL2 O 6MHz 110 VSSA I GND 111 VDDA I Not used 112 R O R for OSD Teletext 113 G O G for OSD Teletext 114 B I B for OSD Teletext 115 VSSA I GND 116 VDDA I 2.5V 117 CVBS2 I Video for Teletext 118 VSSA I GND 119 VDDA I 2.5V 120 CVBS1B I Video for Teletext 121 CVBS1A I Video for Teletext 122 VSSA I GND 123 VDDA I 2.5V 124 P5.0 I AFT for tuner 125 P5.1(KEY1) I Key scan data 1 [ON:H] 126 P5.2 I AGC for tuner 127 P5.3(KEY2) I Key scan data 2 [ON:H] 128 TMODE I Test purpose

1-8 (No.YA169)

2.2.3 SUB CPU PIN FUNCTION (IC7807)

Pin No. Pin name I/O Function

1 (SYSTEM0) I GND 2 (SYSTEM3) I GND 3AVCC -5V 4 X2 - Sub clock 5 X1 - Sub clock 6 VCL - Internal down voltage 7 RES I Reset [Reset : L] 8 TEST I Operation test for SUB CPU

9VSS -GND 10 OSC2 O 10MHz oscillation for system clock 11 OSC1 I 10MHz oscillation for system clock 12 VCC - 5V 13 NC O Not used 14 NC O Not used 15 BL_D2 O Back light 20ms delay for LCD panel [On:L] 16 BL_D1 O Back light 10ms delay for LCD panel [On:L] 17 I2C_STOP O Not used 18 BL_ON O Back light reset for LCD panel [Reset:L] 19 NC O Not used 20 NC O Not used 21 NC O Not used 22 NC O Not used 23 SDA1 I/O 24 A.DIM O Not used 25 SCL1 O 26 SDA0 I/O 27 SCL0 O 28 NC O Not used 29 NC O Not used 30 NC O Not used 31 NC O Not used 32 NC O Not used 33 NC O Not used 34 NC O Not used 35 NMI I Port for writing on board [Writning:L] 36 NC O Not used 37 (HD) I Not used 38 NC O Not used 39 (REMO) I Not used 40 NC O Not used 41 P85 -/I Not used 42 P86 - Not used 43 P87 - Not used 44 SCK3 O Port for writing on board 45 RXD I Port for writing on board 46 TXD O Port for writing on board 47 (PROTECTOR0) I Not used 48 NC O Not used 49 RXD2 I Port for communication (Main CPU) 50 TXD2 O Port for communication (Main CPU) 51 NC O Not used 52 (ACTIVE) I Not used 53 VD I Vertical sync 54 (REC_DET) I Not used 55 (PSS) I Not used 56 (ALARM) I Not used 57 (SYSTEM2) I Not used 58 (SYSTEM1) I Not used 59 (PROTECTOR1) I Not used 60 (AMP_PRO2) I Not used 61 (AMP_PRO1) I Not used 62 EE_CDS I Not used 63 (KEY_IN1) I Not used 64 (KEY_IN2) I Not used

C bus data (For Sub memory)

C bus clock (For Sub memory)

C bus data (For general)

C bus clock (For general)

(No.YA169)1-9

SECTION 3

DISASSEMBLY

3.1 DISASSEMBLY PROCEDURE

CAUTION:

Since this model is a laminating structure assembly, please perform in following order in the case of disassembling.

3.1.1 REMOVING THE STAND ASS'Y (Fig.3-1-1)

(1) Remove the 2 screws [A], and remove the COVER. (2) Remove the 4 screws [B], and remove the STAND ASS'Y.

JACK COVER(L)

JACK COVER(R)

STAND COVER

3.1.2 REMOVING THE REAR COVER (Fig.3-1-1, Fig.3-1-2)

• Remove the STAND ASS'Y. (1) Remove the JACK COVER(R) and JACK COVER(L). (2) Remove the 7 screws [C], 3 screws [D], 4 screws [E], and

remove the REAR COVER.

STAND

Fig.3-1-1

REAR COVER

1-10 (No.YA169)

Fig.3-1-2

3.1.3 REMOVING THE FAN BRACKET, REGULATOR PWB AND POWER CORD (Fig.3-1-3)

• Remove the STAND ASS'Y.

• Remove the REAR COVER.

(1) Disconnect the wire(CONN. [Y]) of COOLING FAN. (2) Remove the 5 screws [F], and remove the FAN BRACKET. (3) Remove the REGULATOR PWB, and disconnect the

POWER CORD.

COOLING FAN

(4) Remove the 1 screw [G], and remove the POWER CORD

HOLDER.

REGULATOR PWB

3.1.4 REMOVING THE RECEIVER PWB (Fig.3-1-4)

• Remove the STAND ASS'Y.

• Remove the REAR COVER. (1) Remove the 2 screws [H] and 2 screws [J], then remove the

TERMINAL BASE.

TERMINAL BASE

(2) Remove the 5 screws [K], and remove the RECEIVER

PWB.

FAN BRACKET

Fig.3-1-3

RECEIVER PWB

POWER CORD

POWER CORD HOLDER

3.1.5 REMOVING THE FRONT CONTROL PWB AND FRONT SENSOR PWB (Fig.3-1-5)

• Remove the STAND ASS'Y.

• Remove the REAR COVER. (1) Remove the 2 screws [L], and remove the CONTROL

KNOB.

(2) Remove the 3 screws [N], then remove the FRONT

EARTH PLATE

CONTROL PWB and FRONT SENSOR PWB.

CONTROL KNOB

Fig.3-1-4

FRONT CONTROL PWB

FRONT SENSOR PWB

CLAMP

HARNES( F,U,T),"S" WIRE

Fig.3-1-5

(No.YA169)1-11

3.1.6 REMOVING THE VIDEO PWB (Fig.3-1-6)

• Remove the STAND ASS'Y.

• Remove the REAR COVER. (1) Remove the 2 screws [N] and 1 screws [P], then remove

the JACK BASE. (2) Remove the 4 screws [Q], and remove the VIDEO PWB. (3) Remove the 2 screws [R], and remove the TUNER PWB

BASE. (4) Remove the 4 screws [S], and remove the TUNER PWB

and MSP PWB.

3.1.7 REMOVING THE MI-COM & DIST PWB (Fig.3-1-7)

• Remove the STAND ASS'Y.

• Remove the REAR COVER. (1) Remove the 7 screws [T], and remove the VIDEO PWB

BRACKET.

(2) Remove the 4 screws [U], and remove the MI-COM & DIST

PWB from VIDEO PWB BRACKET.

VIDEO PWB

MI-COM&DIST PWB

JACK BASE

Fig.3-1-6

VIDEO PWB BRACKET

TUNER PWB

MSP PWB

TUNER PWB BASE

3.1.8 REMOVING THE POWER PWB (Fig.3-1-8)

• Remove the STAND ASS'Y.

• Remove the REAR COVER.

• Remove the FUN BRACKET.

• Remove the POWER CORD.

• Remove the VIDEO PWB. (1) Remove the 4 screws [X], and remove the AV JACK

BRACKET. (2) Remove the 6 screws [Y], and remove the POWER PWB. (3) Remove the 6 screws [Z], and remove the POWER PWB

BASE.

AV JACK BRACKET

Fig.3-1-7

POWER PWB

POWER PWB BASE

1-12 (No.YA169)

Fig.3-1-8

3.1.9 REMOVING THE SPEAKER (Fig.3-1-9A, Fig.3-1-9B)

• Remove the STAND ASS'Y.

• Remove the REAR COVER.

• Remove the POWER CORD. (1) Remove the 5 screws [a], and remove the SPEAKER BOX.

SPEAKER BOX

Fig.3-1-9A

(2) Remove the 4 screws [b], and remove the SPEAKER (L/R). (3) Remove the 4 screws [c], and remove the DUCT COVER/

DUCT BASE.

NOTE:

Since the speaker is attached in a certain direction, attach the speaker in the same correct direction as it has been attached.

DUCT BASE/DUCT COVER

SPEAKER

㧔R㧕

Fig.3-1-9B

SPEAKER

㧔L㧕

(No.YA169)1-13

3.1.10 REMOVING THE LCD PANEL (Fig.3-1-10C, Fig.3-1-10A, Fig.3-1-10B)

• Remove the STAND ASS'Y.

• Remove the REAR COVER.

• Remove the POWER CORD.

• Remove the RECEIVER PWB.

• Remove the FRONT CONTROL PWB.

• Remove the FRONT SENSOR PWB.

• Remove the VIDEO PWB.

• Remove the MI-COM & DIST PWB

• Remove the POWER PWB. (1) Remove the 2 screws [a], and remove the 2 CENTRE

FRAMES.

CENTRE FRAME

Fig.3-1-10A

(2) Remove the 2 screws [b] and 2 screws [c], then remove the

RIGHT FRAME.

(3) Remove the 2 screws [b] and 2 screws [c], then remove the

LEFT FRAME. (4) Remove the 2 screws [d], and remove the TOP FRAME. (5) Remove the 3 screws [e] and 2 screws [f], then remove the

BOTTOM FRAME.

(6) Remove the 8 screws [g] and 2 screws [h], then remove the

LCD PANEL.

NOTE:

The LCD PANEL is fixed to the FRONT PANEL (at the back side) by using double-side adhesive tapes. To remove the LCD PANEL, remove the adhesive tape on the FRONT PANEL slowly.

RIGHT FRAME

TOP FRAME

LEFT FRAME

BOTTOM FRAME

Fig.3-1-10B

1-14 (No.YA169)

Fig.3-1-10C

3.1.11 REMOVING THE LCD PANEL

3.1.11.1 REMOVING THE CONTROL PWB

• Place the LCD PANEL with its backside facing upward. Be careful not to damage the surface of the screen. (1) Remove the 2 screws [A], and remove the CONTROL

PWB COVER.

(2) Remove the claws in the connectors [FPC RIGHT] and

[FPC LEFT], and pull out to remove the FLEXIBLE PWB.

NOTE:

Be careful not to damage the FLEXIBLE PWB. Especially during assembly procedure, be careful not to insert the FLEXIBLE PWB in the Panel.

(3) Remove the 2 screws [B], and remove the CONTROL

PWB.

[Confirmation after replacement]

• Confirm that voltage of 10 pin (B/L On/Off) in the connector

[CNI1] is approx.5.0V.

• Confirm that the voltage in output of the fuses [F1] and [F2]

in the connector [CNI1] is approx.5.0V.

3.1.11.2 REMOVING THE INVERTER PWB

(1) Remove the 5 screws [C], and remove the INVERTER

PWB COVER.

(2) Pull out and remove the wires from connectors [CN4]-

[CN15] (12 connectors in total).

(3) Remove the 4 screws [D], and remove the INVERTER

PWB.

[Confirmation after replacement]

• Confirm that the voltage in output of the fuses [F1] and [F2] in the connector [CN1] and the fuses [F3] and [F4] in the connector [CN2] is 16V.

• Confirm that the voltage in input of the TRANSFORMER in the Inverter Board is 8V.

• Be careful about high voltage (approx. AC900V) in output.

FUSE

OUTPUT

CONTOROL PWB INVERTER PWB

CONNECTOR

OUTPUT

TRANSFORMER

GND 8V 8V 8V 8V GND

INPUT

TRANSFORMER

FUSE

(F3, F4)

[CN4㨪CN15]

INVERTER PWB

INVERTER PWB COVER

CONTROL PWB COVER

FLEXIBLE

CN2

FUSE

(

)

F1, F2

CN1

PWB

CNI1

FRC

RIGHT

CONTROL PWB

FRC

LEFT

CNT1

FUSE

(F1, F2)

FRONT

(No.YA169)1-15

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