JVC LT-42P789 Schematic

SERVICE MANUAL

YA589<Rev.001>20086SERVICE MANUAL

LCD FLAT TELEVISION

LT-42P789/C

BASIC CHASSIS

FN3

There may be multiple versions of this TV model. The TV version is identified by the letters next to the model number on the TVs Rating and Model No. labels. (See illustration). Use the service manual that matches the version of the TV.

No.YA590: LT-32P679 No.YA589: LT-42P789 No.YA591: LT-47P789

No.YA592

: LT-32E479, LT-32EM49 No.YA593: LT-42X579, LT-42EM59 No.YA594: LT-47X579, LT-47EM59

MODEL NAME

LT-42P789

MODEL NO.

RATING LABEL (REAR)

MODEL NO. LABEL (SIDE)

TABLE OF CONTENTS

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

2 SPECIFIC SERVICE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

3 DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8

4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-15

5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17

VERSION

CAA

No.YA589<Rev.001>

2008/6

SPECIFICATION

Items Contents

Dimensions ( W × H × D ) 101.4 cm × 73.4 cm × 29.6 cm (40" × 29" × 11-3/4") [with stand]

101.4 cm × 67.7 cm × 11.7 cm (40" × 26-3/4" × 4-3/4") [without stand]

Mass 26.0 kg (57.2 lbs) [with stand]

Power Input AC120 V , 60 Hz

Power Consumption 247W (Max)

TV RF System (Analog / Digital)

Color System (Analog) NTSC

Stereo System (Analog) BTSC (Multi Channel Sound)

Teletext System (Analog) Closed caption (T1-T4 / CC1-CC4)

TV Receiving Channels and Frequency (Analog)

TV / CATV Total Channel 191 Channels

Intermediate Frequency (Analog)

Color Sub Carrier Frequency (Analog) 3.58 MHz

LCD Panel 42V-inch wide aspect (16:9) Screen Size Diagonal: 106.7 cm (H: 93.0 cm × V: 52.3 cm) Display Pixels Horizontal : 1920 dots × Vertical : 1080 dots

Audio Power Output 10 W + 10 W Speaker 4.0 cm × 16.0 cm, oval type(Oblique corn) × 2

Antenna Terminal (VHF/UHF, ATSC / DIGITAL CABLE IN)

Digital Input [INPUT-1/2/3]

Video / Audio Input [INPUT-4]

Video / Audio Input [INPUT-5]

Audio output (Fix) 500 mV (rms), Low impedance, RCA pin jack × 2 Digital Audio Optical Output Digital SPDIF × 1 Photo Viewer / Service USB connector × 1 Remote Control Unit RM-C1480 (AA/R6 battery × 2)

Digital(Video/Audio) HDMI 2-row 19pin connector × 3

Component Video

VHF Low

VHF High

Video IF

Sound IF

Analog (Audio) 500mV(rms) (-4dBs), high impedance, RCA pin jack × 2

1080i / 720p

480p / 480i

S-Video Mini-DIN 4 pin × 1

1080i / 720p

480p / 480i

Design & specifications are subject to change without notice.

24.0 kg (52.8 lbs) [without stand]

Analog

CCIR (M)

Digital

ATSC terrestrial / Digital cable

02 ch - 06 ch : 54 MHz - 88 MHz 07 ch - 13 ch : 174 MHz - 216 MHz

UHF

14 ch - 69 ch : 470 MHz - 806 MHz

CATV

54 MHz - 804 MHz Low Band : 02 - 06 High Band : 07 - 13 Mid Band : 14 - 22 Super Band : 23 - 36 Hyper Band : 37 - 64 Ultra Band : 65 - 94, 100 - 135 Sub Mid Band : 01, 96 - 99

45.75 MHz

41.25 MHz (4.5 MHz)

F-type connector, 75Ω unbalanced, coaxial × 1

(Digital-input terminal is not compatible with picture signals of personal computer) Video: Supported format: 1080p / 1080i / 720p / 480p / 480i Audio: 2ch L-PCM, 32 / 44.1 / 48 KHz, 16 / 20 / 24 bit

RCA pin jack × 3 Y : 1 V (p-p) (Sync signal: 0.35V(p-p), 3-value sync.), 75 Ω Pb/Pr : ±0.35V(p-p), 75 Ω Y : 1 V (p-p), Positive (Negative sync.), 75 Ω Cb/Cr : 0.7V(p-p), 75 Ω

Y: 1 V (p-p), Positive (Negative sync.), 75 Ω

C: 0.286V (p-p) (Burst signal), 75 Ω Video 1 V (p-p), Positive (Negative sync.), 75 Ω, RCA pin jack × 1 Audio 500 mV (rms), High impedance, RCA pin jack × 2

RCA pin jack × 3

Y : 1 V (p-p) (Sync signal: 0.35V(p-p), 3-value sync.), 75 Ω

Pb/Pr : ±0.35V(p-p), 75 Ω

Y : 1 V (p-p), Positive (Negative sync.), 75 Ω

Cb/Cr : 0.7V(p-p), 75 Ω Video 1 V (p-p), Positive (Negative sync.), 75 Ω, RCA pin jack × 1 Audio 500 mV (rms), High impedance, RCA pin jack × 2

1-2 (No.YA589<Rev.001>)

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) 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.

(6) 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

GOOD EARTH GROUND

1500 10W

PLACE THIS PROBE ON EACH EXPOSED ME TAL PAR T

(No.YA589<Rev.001>)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. The temperature sensor that protects the unit will be activated when internal temperature exceeds the pre-determined level and power will be turned off automatically.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.

Ventilation hole

*The drawing may differ from the actual appearance.

1.2.3 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.

It fixes in a band.

TV STAND

*The drawing may differ from the actual appearance.

1.2.4 NOTES ON HANDLING

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.

1.2.2 INSTALLATION REQUIREMENTS

Ensure that the minimal distance is maintained, as specified below, between the unit with and the surrounding walls, as well as the floor etc.Install the unit on stable flooring or stands.Take precautionary measures to prevent the unit from tipping in order to protect against accidents and earthquakes.

200 mm

7 7/8 inch

150 mm

5 7/8 inch

*The drawing may differ from the actual appearance.

150 mm

5 7/8 inch

200 mm

7 7/8 inch

50 mm

2 inch

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.

1-4 (N o.YA 589<R ev.001>)

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 color.

(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.

SECTION 2

SPECIFIC SERVICE INSTRUCTIONS

2.1 FEATURES

TeleDock

By inserting your iPod into the TeleDock, you can display movies or music on your TV from your iPod. Also, while inserted you can recharge your iPod.

Item Contents

Support Models of iPod iPod: 4G/Photo/5G/Classic

iPod nano: 1G/2G/3G iPod mini: 1G/2G iPod touch

Support format for movie H.264, MPEG-4

Support format for audio AAC, MP3, AppleLossless, WAV,

AIFF

Support format for picture JPEG, BMP, GIF, TIFF, PSD, PNG

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 color.

(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).

Color Management

This function ensures dull colors are compensated to produce natural hues.

Smart Picture

This function detects the APL (Average Picture Level) and adjusts the contrast suitable for what you are watching.

DIGITAL VNR

This function cuts down the amount of noise in the original picture.

MPEG Noise Reduction

This function effects the block noise removal and mosquito NR simultaneously.

Built in ATSC (Advanced Television Systems Committee) TUNER

This TV can receive both Digital broadcasting (ATSC) and Analog broadcasting.

(No.YA589<Rev.001>)1-5

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. 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.

2.2.1.1 SPECIFICATIONS

The following table shows the specifications of this unit.

Item Specifications

Maximum dimensions ( W × H × D ) 98.3 cm × 57.6 cm × 5.2 cm

Weight 13.0 kg

Effective screen size Diagonal: 106.7 cm (H: 93.0 cm × V: 52.3 cm)

Aspect ratio 16 : 9

Drive device / system a-Si-TFT active matrix system

Resolution Horizontally 1920 × Vertically 1080 × RGB <W-UXGA> 6220800 dots in total

Pixel pitch (pixel size) Horizontally: 0.1615 mm, Vertically: 0.4845 mm

Displayed colour 16777216 colours 256 colours for R G and B

Brightness 500 cd/m

Contrast ratio 2000 : 1

Response time 6.5 ms

View angle Horizontally: 176°, Vertically: 176°

Surface polarizer Anti-Glare type Low reflective coat

Colour filter Vertical stripe

Backlight Cold cathode fluorescent lamp × 20

Power supply voltage in LCD 12 V

Power supply voltage in inverter 24 V

Panel interface system LVDS (Low Voltage Differential Signaling)

2.2.1.2 PIXEL FAULT

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

 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.

 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 color and find out the cell that is not lighting.

 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 color and find out the cell that is flashing on and off.

1-6 (No.YA589<Rev.001>)

2.2.2 SUB MICRO COMPUTER (CPU) FUNCTION [SIGNAL PWB: IC2501]

No.

10 RESET I CPU reset [Reset = L]

11 XOUT O Oscillation for system clock

12 VSS - GND

13 XIN I Oscillation for system clock

14 VCC1 - +3.3V power supply

15 NMI I Non-maskable interrupt [H fixed]

16 MCU_RESET2 I

17 POWER_KEY I

18 IR_33 I Remote control

19 P8_1 - Not used

20 P8_0 - Not used

21 LED_DIMMING O Brightness control for POWER LED [Bright = H]

22 LED_ON O Lighting for POWER LED [On = H]

23 AC_IN I Not used

24 ILLUMI_ON O Not used

25 VGA_DET I Not used

26 ILL_DIMMING O Not used

27 RX_NF I Serial data receive for iPod

28 TX_NF O Serial data transmission for iPod

29 TXD1 O

30 RXD1 I Data receive (serial) for external programming

31 CLK1 I/O Clock for external programming

32 RTS1 O Busy for external programming

33 MCU_TXD O Serial data transmission for main CPU

34 MCU_RXD I Serial data receive for main CPU

35 P6_1 - Not used

36 P6_0 - Not used

37 P5_7 - Not used

38 P5_6 - Not used

39 HOLD I CPU mode select [L fixed]

40 P5_4 - Not used

41 P5_3 - Not used

42 P5_2 - Not used

43 P5_1 - Not used

44 P5_0 - Not used

45 nRESET O Reset for iPod controller [Reset = L]

46 CP_READY I Data ready for iPod controller

47 NF_CNTL2 O Lighting for iPod DOCK LED [On = H]

48 NF_CNTL1 O Lighting for iPod DOCK LED [On = H]

49 I2C_SDA I/O I2C bus (data) for iPod controller

50 I2C_SCL O I2C bus (clock) for iPod controller

Pin name I/O Function

1 P9_4 - Not used

2 P9_3 - Not used

3 P9_2 - Not used

4 P9_1 - Not used

5 P9_0 - Not used

6 BYTE I Data bus width select [L fixed]

7 CNVSS I CPU mode select [Normal = L]

8 P8_7 - Not used

9 XRES I Not used

Interrupt detection for 24V power supply [Error = L]

Interrupt detection for mecanical POWER SW [On = L]

Data transmission (serial) for external programming

Pin No.

51 EDID_WP O

52 NF_PPON O Not used

53 NF_OC O Not used

54 DET_NF I Detection for iPod connecting [Detect = L]

55 PFC_POW O Power on/off control for PFC [On = L]

56 CTL_SW O

57 HP_DET I Not used

58 HP_WDOG I Watch dog reset for main CPU

59 P3_1 - Not used

60 VCC2 - +3.3V power supply

61 P3_0 Not used

62 VSS - GND

63 RESET_TU O Reset for tuner [Reset = L]

64 VCCH_RST O Reset for Vcch of main CPU [Reset = L]

RESET%_TRIDENT

RESET_STV8258

67 S_MUTE O Speaker output muting [Muting = H]

68 A_MUTE O Audio line output muting [Muting = H]

69 HP_MUTE O Not used

70 MAIN_POWER O

71 P1_7 - Not used

72 P1_6 - Not used

73 P1_5 - Not used

74 BKLT_CNTL O Not used

75 P1_3 - Not used

76 REG_SW1 O Power on/off control for regulator IC [On = H]

77 REG_SW2 O Power on/off control for regulator IC [On = H]

78 REG_SW3 O Power on/off control for regulator IC [On = H]

79 P0_7 - Not used

80 P0_6 - Not used

81 SDA_EEP I/O I

82 SCL_EEP O I

83 P0_3 - Not used

84 P0_2 - Not used

85 P0_1 - Not used

86 P0_0 - Not used

87 P10_7 - Not used

88 P10_6 - Not used

89 P10_5 - Not used

90 P10_4 - Not used

91 LB_PRO I Low-B protect detection [Error protection = H]

92 P10_2 - Not used

93 KEY2 I Side key scan voltage (MENU CH+/-)

94 AVSS - GND

95 KEY1 I Side key scan voltage (INPUT VOL+/-)

96 VREF I Reference voltage [H fixed]

97 AVCC - +3.3V power supply

98 P9_7 - Not used

99 P9_6 - Not used

100 P9_5 - Not used

Pin name I/O Function

Programming control for EDID ROM [Protection = H]

S-video signal select for INPUT-4 or iPod [iPod = H]

Reset for main CPU & flash memory [Reset = L]

O Not used

Power on/off control for main power supply [On = L]

C bus (data) for EEPROM

C bus (clock) for EEPROM

(No.YA589<Rev.001>)1-7

SECTION 3

DISASSEMBLY

3.1 CAUTION AT DISASSEMBLY

• Make sure that the power cord is disconnected from the outlet.

• Pay special attention not to break or damage the parts.

• Make sure that there is no bent or stain on the connectors before inserting, and firmly insert the connectors.

• Be sure to reattach the wire clamps removed during the procedure to the original positions. (Attaching the wire clamps in wrong positions may affect the performance.)

REFERENCE:

When removing each board, remove the connector if necessary. The operation is easier if you write down the connection points (connector numbers) of the connector. For connection of each board, refer to the "WIRING DIAGRAM" of the Standard Circuit Diagram.

3.2 DISASSEMBLY PROCEDURE

3.2.1 REMOVING THE REAR COVER (Fig.3-1)

(1) Remove the 1 screw [A]. (2) Remove the POWER CORD COVER. (3) Remove the POWER CORD. (4) Remove the 1 screw [B], 9 screws [C] and the 5 screws [D]. (5) Remove the REAR COVER.

3.2.8 REMOVING THE SPEAKER (Fig.3-1)

• Remove the REAR COVER. (1) Remove the 2 screws [L]. (2) Remove the SPEKAER. (3) Follow the same steps when removing the other hand

SPEAKER.

3.2.2 REMOVING THE BACK BRACKET (Fig.3-1)

• Remove the REAR COVER. (1) Remove the 4 screws [E]. (2) Remove the BACK BRACKET.

3.2.3 REMOVING THE POWER PWB (Fig.3-1)

• Remove the POWER CORD.

• Remove the REAR COVER.

• Remove the BACK BRACKET. (1) Remove the 10 screws [F]. (2) Remove the POWER PWB.

3.2.4 REMOVING THE SIGNAL PWB (Fig.3-1)

• Remove the REAR COVER.

• Remove the BACK BRACKET. (1) Remove the 2 screws [G]. (2) Remove the TERMINAL BRACKET. (3) Remove the 8 screws [H]. (4) Remove the SIGNAL PWB.

3.2.5 REMOVING THE SW PWB (Fig.3-1)

• Remove the REAR COVER. (1) Remove the 2 screws [J]. (2) Remove the SW PWB.

3.2.6 REMOVING THE CONTROL KNOB (Fig.3-1)

• Remove the REAR COVER.

• Remove the SW PWB. (1) Remove the 2 screws [K]. (2) Remove the CONTROL KNOB.

3.2.7 REMOVING THE LED PWB (Fig.3-1)

• Remove the REAR COVER. (1) Remove the 2 hooks [a]. (2) Remove the LED PWB.

3.2.9 REMOVING THE STAND (Fig.3-1)

(1) Remove the 4 screws [M]. (2) Remove the STAND.

3.2.10 REMOVING THE TELEDOCK (Fig.3-1)

• Remove the REAR COVER.

• Remove the STAND. (1) Remove the 4 screws [N], 2 screws [P] and the 4 screws [Q]. (2) Remove the BOTTOM FRAME. (3) Remove the 2 screws [R]. (4) Remove the TELEDOCK. (5) Remove the 2 screws [S]. (6) Remove the DAMPER. (7) Remove the 2 screws [T]. (8) Remove the DOCK REAR CASE. (9) Remove the 4 screws [U].

(10) Remove the DOCK PWB.

NOTE:

As the TELEDOCK cannot be disassembled/assembled with the COVER closed, the TELEDOCK may not be removed depending on the COVER open/close condition. If the COVER is in the condition where the TELEDOCK usually cannot be removed, give enough force to open the COVER yet not to break it, and then remove the TELEDOCK.

3.2.11 REMOVING THE LCD PANEL UNIT (Fig.3-1)

• Remove the REAR COVER.

• Remove the STAND.

• Remove the BOTTOM FRAME. (1) Remove the 4 screw [V] and the 3 screws [W]. (2) Remove the MIAN BASE. (3) Remove the 4 screws [X]. (4) Remove the LCD SUPPORT BRACKET. (5) Remove the LCD PANEL UNIT from the FRONT PANEL.

1-8 (No.YA589<Rev.001>)

POWER CORD COVER

POWER CORD

POWER PWB

SIDE BRACKET

REAR COVER

BACK BRACKET

MAIN BASE

SIGNAL PWB

SIDE BRACKET

TERMINAL BASE

LED PWB

SW PWB

CONTROL KNOB

STAND

BOTTOM FRAME

DOCK FRAME

DOCK PWB

LCD PANEL UNIT

FRONT PANEL

FRONT

SPEAKER

Fig.3-1

DOCK REAR CASE

FRONT

DOCK CASE BRACKET

SPEAKER

DOCK SHAFT

DOCK FRONT CASE

DAMPER

FRONT

(No.YA589<Rev.001>)1-9

3.3 DISASSEMBLY PROCEDURE (LCD PANEL UNIT)

3.3.1 REMOVING THE LCD CONTROL PWB (Fig.3-2)

• Remove the REAR COVER.

• Remove the MAIN BASE. (1) Remove the 4 screws [A]. (2) Remove the LCD CONTROL PWB COVER. (3) Remove the LCD CONTROL PWB.

LCD CONTROL PWB COVER

INVERTER PWB COVER

3.3.2 REMOVING THE INVERTER PWB (Fig.3-2)

• Remove the REAR COVER. (1) Remove the 6 screws [B]. (2) Remove the INVERTER PWB COVER. (3) Remove the INVERTER PWB. (4) Follow the same steps when removing the other

INVERTER PWB.

INVERTER PWB (MASTER)

LCD PANEL UNIT

LCD CONTROL PWB

Z Z Z Z

Z Z Z

Z Z

Fig.3-2

INVERTER PWB (SLAVE)

1-10 (No.YA589<Rev.001>)

3.4 MEMORY IC REPLACEMENT

• This model uses the memory IC.

• This memory IC stores data for proper operation of the video and drive circuits.

• When replacing, be sure to use an IC containing this (initial value) data.

3.4.1 MEMORY IC TABLE

Simbol Number of pins Mounting PWB Main content of data

IC2001

IC2004

IC2007

IC2503

8-pin SIGNAL PWB Setting data of HDMI-1 is memorized.

8-pin SIGNAL PWB Setting data of HDMI-2 is memorized.

8-pin SIGNAL PWB Setting data of HDMI-3 is memorized.

8-pin SIGNAL PWB Setting value of IC2501(SUB CPU) is memorized.

3.4.2 MEMORY IC REPLACEMENT PROCEDURE

1. Power off

Switch off the power and disconnect the power plug.

2. Replace the memory IC

Be sure to use a memory IC written with the initial setting data.

3. Power on

Connect the power cord to the wall outlet and switch on the power.

4. Receiving channel setting

Refer to the OPERATING INSTRUCTIONS (USER'S GUIDE) and set the receive channels (Channels Preset) as described.

5. User settings

Check the user setting items according to the "FACTORY SETTING ITEM" table. Where these do not agree, refer to the OPERATING INSTRUCTIONS (USER'S GUIDE) and set the items as described.

6. SERVICE MODE setting

Verify what to set in the SERVICE MODE, and set whatever is necessary(Fig.1) . Refer to the SERVICE ADJUSTMENT for setting.

3.4.3 SERVICE MODE SETTING ITEMS

SERVICE MODE SCREEN

Factory Menu

1.White Balance

2.White Balance Base

3.M16 EEPROM EDIT

4.I2C Stop

5.Version

Select the "2.White Balance Base".

R Gain

G Gain

B Gain

R Offset

G Offset

B Offset

Fig.3-4

Setting items Settings Item No.

1.White Blance

R Gain G Gain

Fixed

B Gain R Offset G Offset B Offset

2.White Blance Base

R Gain

G Gain

Adjust

B Gain R Offset G Offset B Offset

3.M16 EEPROM EDIT Fixed ---

4.I2C Stop Fixed ---

5.Version Fixed ---

(No.YA589<Rev.001>)1-11

3.4.4 SETTINGS OF FACTORY SHIPMENT

3.4.4.1 BUTTON OPERATION 3.4.4.2 REMOTE CONTROL DIRECT OPERATION

Setting item Setting position

POWER Off

CHANNEL CABLE-01

VOLUME 20

INPUT TV

3.4.4.3 REMOTE CONTROL MENU OPERATION

 PICTURE ADJUST

Customers can adjust the picture setting of menu screen as their own like but the picture standard value during factory shipment is as below.

<NTSC(ATV, CVBS, S)>

Setting item STANDARD DYNAMIC GAME THEATER

Tint 46 46 46 48 Color 76 80 76 60 Picture 50 50 48 48 Bright 36 36 36 40 Detail 30 45 30 0 Backlight 40 100 40 15 Color Temp Natural Cool Cool Warm Color Management On On On Off Dynamick Gamma On On Off Off Smart picture On Off On On Digital VNR Low Low Low Low MPEG NR On On On On Natural Cinema Off Off Off Off

INPUT TV

CHANNEL CABLE-01

VOLUME 20

MUTING OFF

DISPLAY OFF

ASPECT NTSC,480i/p: Panorama

SLEEP OFF

VIDEO STATUS Dynamic

SOUND STATUS Speech

Setting item Setting position

720p,1080i/p: Full

<480i/480p/720p/1080i/1080p (DTV, Component , HDMI)>

Setting item STANDARD DYNAMIC GAME THEATER

Tint 46 45 46 48 Color 80 82 80 65 Picture 46 47 44 46 Bright 50 44 50 52 Detail 15 20 15 0 Backlight 40 100 40 15 Color Temp Natural Cool Cool Warm Color Management On On On Off Dynamick Gamma On On Off Off Smart picture On Off On On Digital VNR Low Low Low Low MPEG NR On On On On Natural Cinema Off Off Off Off

1-12 (No.YA589<Rev.001>)

 DISPLAY

 SOUND

Setting item Setting position

Video Input Label Default

Photo Viewer Interval :5

Aspect Ratio NTSC,480i/p Panorama

720p,1080i/p Full

 TV

Setting item Setting position

Closed Caption Off

CC Setting Analog CC CC1

Digital CC Service1

Font Default

Font Size Default

Font Style Default

Text Color Default

Text Opacity Default

BG Color Default

BG Opacity Default

Edge Color Default

Tuner Mode Cable

Edit Channel Setting Ch Page

V-Chip Do Not Block

Setting item Setting position

MTS Stereo

Digital Audio(ML) English

Surround Off

Sound Status Speech

STEP

100Hz 330Hz 1kHz 3.3kHz 10kHz

USER 00000

SPEECH 0 2662

JAZZ 6 0 -2 2 3

CLASSIC53223

ROCK 83024

 POWER

Setting item Setting position

Sleep Timer Off

Power Indicator High

Illumination High

 SETTING

Setting item Setting position

Time Zone

D.S.T.

Language

Noise Mute

Front Panel Lock

Transparency

Auto Shut Off

Auto Demo

Optical Out

Pacific

Off

English

Off

No Setting (Auto Start)

PCM

(No.YA589<Rev.001>)1-13

3.5 REPLACEMENT OF CHIP COMPONENT

3.5.1 CAUTIONS

(1) Avoid heating for more than 3 seconds. (2) Do not rub the electrodes and the resist parts of the pattern. (3) When removing a chip part, melt the solder adequately. (4) Do not reuse a chip part after removing it.

3.5.2 SOLDERING IRON

(1) Use a high insulation soldering iron with a thin pointed end of it. (2) A 30w soldering iron is recommended for easily removing parts.

3.5.3 REPLACEMENT STEPS

1. How to remove Chip parts

2. How to install Chip parts

[Resistors, capacitors, etc.]

(1) As shown in the figure, push the part with tweezers and

alternately melt the solder at each end.

(2) Shift with the tweezers and remove the chip part.

[Transistors, diodes, variable resistors, etc.]

(1) Apply extra solder to each lead.

SOLDER

[Resistors, capacitors, etc.]

(1) Apply solder to the pattern as indicated in the figure.

(2) Grasp the chip part with tweezers and place it on the

solder. Then heat and melt the solder at both ends of the chip part.

[Transistors, diodes, variable resistors, etc.]

(1) Apply solder to the pattern as indicated in the figure. (2) Grasp the chip part with tweezers and place it on the

solder.

(3) First solder lead A as indicated in the figure.

(2) As shown in the figure, push the part with tweezers and

alternately melt the solder at each lead. Shift and remove the chip part.

NOTE :

After removing the part, remove remaining solder from the pattern.

1-14 (No.YA589<Rev.001>)

(4) Then solder leads B and C.

SECTION 4

ADJUSTMENT

4.1 ADJUSTMENT PREPARATION

(1) This TV is adjusted by using REMOTE CONTROL UNIT. (2) The adjustment using the REMOTE CONTROL UNIT is made on the basis of the initial setting values. The setting values

which adjust the screen to the optimum condition can be different from the initial setting values.

(3) Make sure that connection is correctly made AC to AC power source. (4) Turn on the power of the TV and measuring instruments for warming up for at least 30 minutes before starting adjustments. (5) If the receive or input signal is not specified, use the most appropriate signal for adjustment. (6) Never touch the parts (such as variable resistors, transformers and condensers) not shown in the adjustment items of this service

adjustment.

4.2 PRESET SETTING BEFORE ADJUSTMENTS

Unless otherwise specified in the adjustment items, preset the following functions with the REMOTE CONTROL UNIT.

Setting item Settings

VIDEO STATUS Standard

COLOR TEMP Natural

COLOR MANAGEMENT Off

NATURAL CINEMA Off

ASPECT FULL

4.4 SERVICE MODE

4.4.1 HOW TO ENTER THE SERVICE MODE

(1) Set to "OFF" using the [SLEEP] key. (2) While "OFF" is displayed, press the [V. STATUS] key and

[DISPLAY] key simultaneously. (3) Enter the SERVICE MODE (Fig.4-1) (4) Select the 2.White balance base from the SERVICE

MODE.

SERVICE MODE SCREEN

Factory Menu

1.White Balance

2.White Balance Base

3.M16 EEPROM EDIT

4.I2C Stop

5.Version

4.3 MEASURING INSTRUMENT AND FIXTURES

• Signal generator (Pattern generator) [NTSC]

• Remote control unit

4.4.3 SERVICE MODE SELECT KEY LOCATION

[SLLEP]

[MENU]

[ ]

Select the "2.White Balance Base".

R Gain

G Gain

B Gain

R Offset

G Offset

B Offset

Fig.4-1

4.4.2 HOW TO EXIT THE SERVICE MODE Press the [MENU] key to exit the SERVICE MODE.

[V. STATUS]

[DISPLAY]

4.4.4 CHANGE AND MEMORY OF SETTING VALUE

Remocon Key Contents

[] / [] key Change the setting items up/ down.

[] / [] key Change the setting values up/down.

[OK] key Select the setting items.

4.4.5 HOW TO STORE OF SETTING VALUE

The setting value will be stored automatically when release the REMOTE CONTROL UNIT keys.

(No.YA589<Rev.001>)1-15

4.4.6 INITIAL SETTING VALUES IN THE SERVICE MODE

• Perform fine-tuning based on the "initial values" using the remote control unit when in the SERVICE MODE.

• The "initial values" serve only as an indication rough standard and therefore the values with which optimal display can be achieved may be different from the default values.

• Never change the values of the items ( ) that are not described in ADJUSTMENT PROCEDURE or in the below table as they are fixed values.

Mode Setting item

1. White balance

[Do not adjust]

2. White balance Base R Gain -100 - 100 0

3.M16 EEPROM EDIT

[Do not adjust]

4.I2C Stop ---

5.Version ---

4.5 ADJUSTMENT PROCEDURE

R Gain -100 - 100 0

G Gain -100 - 100 0

B Gain -100 - 100 0

R Offset -100 - 100 0

G Offset -100 - 100 0

B Offset -100 - 100 0

G Gain -100 - 100 0

B Gain -100 - 100 0

R Offset -100 - 100 0

G Offset -100 - 100 0

B Offset -100 - 100 0

Variable

range

Initial setting

value

---

Item

WHITE BALANCE (HIGHLIGHT)

Measuring

instrument

Remote control unit

Signal generator

Adjustment part Description

[2.White balance Base] R Gain (Red Gain) G Gain (Green Gain) B Gain (Blue Gain) R Offset (Red Offset) G Offset (Green Offset) B Offset (Blue Offset)

(1) Receive a NTSC 75% all white signal. (2) Set "VIDEO STATUS" to "Standard". (3) Set "ASPECT" to "Full". (4) Select "COLOR TEMP" to "Natural". (5) Select the 2.White balance base from the SERVICE

MODE.

(6) Set the setting value of <R Offset>(Red Offset), <G

Offset>(Green Offset) and <B Offset>(Blue Offset) to 0.

(7) Adjust to keep one of <R Gain>(Red Gain), <G

Gain>(Green Gain) or <B Gain>(Blue Gain) unchanged, then lower the other two so that the all-white screen is equally white throughout.

NOTE:

Set one or more of <R Gain>, < G　Gain> and <B Gain> to "0".

(8) Check that white balance is properly tracked from low light

to high light. If the white balance tracking is deviated, adjust to correct it.

1-16 (No.YA589<Rev.001>)

SECTION 5

TROUBLESHOOTING

5.1 SELF CHECK FUNCTIONS

5.1.1 OUTLINE

This model has a self check function given below. When an abnormality has been detected, the power is turned off and the POWER LED flashes to inform of the failure. An abnormality is detected by the signal input state of the control line connected to the microcomputer.

5.1.2 SELF CHECK ITEMS

Detection item Detection content

Low bias line short protection

5.1.3 METHOD OF DISPLAY WHEN A RASTER IS NOT OUTPUT

In the state where a raster is not output by breakdown of the set, an error is displayed by blink of the POWER LED.

Type of error POWER LED flash cycle

Low bias line short protection LED turning on and off at 2 seconds intervals.

If an error is detected, the power is turned off. Shortly after the power is turned off, the POWER LED will be blinked. Power cannot be turned on until the power cord takes out and inserts, after the power is turned off.

Confirm the operation of the low bias (3.3V/5V/ 12V/24V) protection circuit.

3.3V: Q7004 5V: Q7003 12V: Q7001 24V: IC7019

[SIGNAL PWB]

Diagnosis

signal (line)

LB_PRO At 10 seconds after the power is turned on, the

self-check function starts. If NG is detected during 3000ms, the power is turned off automatically.

Detection timing

(No.YA589<Rev.001>)1-17

Victor Company of Japan, Limited

Display category 12, 3-chome, Moriya-cho, Kanagawa-ku, Yokohama-city, Kanagawa-prefecture, 221-8528, Japan

(No.YA589<Rev.001>)

Printed in Japan

VPT

SCHEMATIC DIAGRAMS

LCD FLAT TELEVISION

LT-42P789/C

DVD-ROM No.SML2008Q1

BASIC CHASSIS

FN3

No.YA589<Rev.001>

2008/6

LT-42P789

STANDARD CIRCUIT DIAGRAM

NOTE ON USING CIRCUIT DIAGRAMS

1.SAFETY

The components identified by the symbol and shading are critical for safety. For continued safety replace safety ciritical components only with manufactures recommended parts.

2.SPECIFIED VOLTAGE AND WAVEFORM VALUES

The voltage and waveform values have been measured under the following conditions.

(1)Input signal : Colour bar signal

(2)Setting positions of each knob/button and variable resistor

(3)Internal resistance of tester

(4)Oscilloscope sweeping time

(5)Voltage values

Since the voltage values of signal circuit vary to some extent according to adjustments, use them as reference values.

: Original setting position when shipped

: DC 20kΩ/V

: H

: V

: Othters

: All DC voltage values

20µs / div

5ms / div

Sweeping time is specified

3.INDICATION OF PARTS SYMBOL [EXAMPLE]

In the PW board

: R1209

R209

Type

No indication

MM PP MPP MF TF BP

TAN

(3)Coils

No unit

Others

(4)Power Supply

Respective voltage values are indicated

(5)Test point

: Test point

(6)Connecting method

: Ceramic capacitor : Metalized mylar capacitor

: Polypropylene capacitor : Metalized polypropylene capacitor : Metalized film capacitor : Thin film capacitor : Bipolar electrolytic capacitor : Tantalum capacitor

: [µH]

: As specified

: B1

: 9V

: Connector

: Receptacle

: Only test point display

: Wrapping or soldering

: B2 (12V

: 5V

)

4.INDICATIONS ON THE CIRCUIT DIAGRAM

(1)Resistors

Resistance value

No unit : [Ω]

K M

Rated allowable power No indication : 1/16 [W]

Others : As specified

Type

No indication

OMR

MFR

MPR

UNFR

Composition resistor 1/2 [W] is specified as 1/2S or Comp.

(2)Capacitors

Capacitance value

1 or higher : [pF]

less than 1

Withstand voltage

No indication : DC50[V]

Others : DC withstand voltage [V]

AC indicated Electrolytic Capacitors

47/50[Example]: Capacitance value [µF]/withstand voltage[V]

: [kΩ]

: [MΩ]

: Carbon resistor

: Oxide metal film resistor

: Metal film resistor

: Metal plate resistor

: Uninflammable resistor

: Fusible resistor

: [µF]

: AC withstand voltage [V]

(7)Ground symbol

: LIVE side ground

: ISOLATED(NEUTRAL) side ground

: EARTH ground

: DIGITAL ground

5.NOTE FOR REPAIRING SERVICE

This model's power circuit is partly different in the GND. The difference of the GND is shown by the LIVE : ( ) side GND and the ISOLATED(NEUTRAL) : ( ) side GND. Therefore, care must be taken for the following points.

(1)Do not touch the LIVE side GND or the LIVE side GND and the ISOLATED(NEUTRAL) side GND simultaneously. if the above caution is not respected, an electric shock may be caused. Therefore, make sure that the power cord is surely removed from the receptacle when, for example, the chassis is pulled out.

(2)Do not short between the LIVE side GND and ISOLATED(NEUTRAL side GND or never measure with a measuring apparatus measure with a measuring apparatus ( oscilloscope, etc.) the LIVE side GND and ISOLATED(NEUTRAL) side GND at the same time. If the above precaution is not respected, a fuse or any parts will be broken.

Since the circuit diagram is a standard one, the circuit and circuit constants may be subject to change for improvement without any notice.

NOTE Due improvement in performance, some part numbers show in the circuit diagram may not agree with those indicated in the part list. When ordering parts, please use the numbers that appear in the Parts List.

)

(No.YA589<Rev.001>)2-1

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