JVC LT-32C50BU, LT-32C50SU Service Manual

YA204200410

SERVICE MANUAL

WIDE LCD PANEL TELEVISION

LT-32C50BU, LT-32C50SU

BASIC CHASSIS

TABLE OF CONTENTS

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

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

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

4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16

5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-23

No.YA204

2004/11

SPECIFICATION

Items Contents

Dimensions ( W × H × D ) 83.4cm × 63.2 cm × 30.0 cm [Included stand]

83.4cm × 56.8 cm × 10.8 cm [TV only]

Mass 19.8kg [Included stand]

17.3kg [TV only]

Power Input AC110 to AC240 V, 50 Hz / 60 Hz

Power Consumption 161W (Standby: 2.8W)

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 VHF

Intermediate Frequency VIF

Colour Sub Carrier Frequency

LCD panel 32V-inch wide aspect (16:9)

Screen Size Diagonal : 80cm (H:69.7cm × V : 39.2cm) Display Pixels Horizontal : 1366 dots × Vertical : 768 dots (W-XGA)

Audio Power Output 10W + 10W

Speaker 6.6cm, round type × 2 (Oblique corn) Aerial terminal (VHF/UHF) F-type connector, 75Ω unbalanced, coaxial EXT-1 / EXT-2 (Input / Output) 21-pin Euro connector (SCART socket ) × 2

EXT-3 (Input) S-Video

EXT-4 (Input) Component Video

625p / 525p / 625i / 525i

PC (RGB) Input D-sub 15pin × 1

Audio output 500mV (rms), Low impedance, RCA pin jack × 2 Headphone 3.5mm stereo mini jack × 1 Remote Control Unit RM-C1811H (AA/R6 dry cell battery × 2)

Design & specifications are subject to change without notice.

SECAM

47MHz to 470MHz

UHF

470MHz to 862MHz

CATV

116MHz to 172MHz / 220MHz to 469MHz

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

SIF

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

PAL

4.43MHz

4.40625MHz / 4.25MHz

NTSC

3.58MHz / 4.43MHz

Mini-DIN 4 pin × 1 Y: 1V (p-p), Positive (Negative sync provided), 75 Ω C: 0.286V (p-p) (Burst signal), 75 Ω

Video

1V (p-p), Positive (Negative sync provided), 75 Ω, RCA pin jack × 1

Audio

500mV (rms), High impedance, RCA pin jack × 2 RCA pin jack × 3

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

1125i

Pb/Pr : ±0.35V(p-p), 75 Ω Y : 1V (p-p), Positive (Negative sync provided), 75 Ω Cb/Cr : 0.7V(p-p), 75 Ω

Audio

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

R/G/B : 0.7V (p-p), 75Ω

HD / VD : 1V (p-p) to 5V (p-p), high impedance < Available signal >

VGA : 640 pixels × 480 pixels (Horizontal : 31.5kHz / Vertical : 60Hz) XGA : 1024 pixels × 768 pixels (Horizontal : 48.4kHz / Vertical : 60Hz)

1-2 (No.YA204)

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.YA204)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

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. Use the supplied screws to firmly attach the supplied hooks (OPTION) to the back of the TV, and use commercially available cord to fix the TV to rigid components such as walls and columns.

Wall

Hook

The hook for fall prevention(option)

It fixes in a band.

TV Stand

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.

150 mm

200 mm

150 mm

200 mm

50 mm

*Diagram differs from actual appearance.

1.2.4 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.YA204)

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.YA204)1-5

SECTION 2

SPECIFIC SERVICE INSTRUCTIONS

2.1 FEATURES

D.I.S.T. (Digital Image Scaling Technology)

This system uses line interpolation to double the number of scanning lines and achieve high resolution, flicker-free picture.

COLOUR MANAGEMENT

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

PICTURE MANAGEMENT

This function makes it easier to see the dark areas when a picture has many dark areas, and makes it easier to see the bright areas when a picture has many bright areas.

ZOOM

This function can change the screen size according to the picture aspect ratio.

2.2 MAIN DIFFERENCE LIST

Item LT-32C50BU LT-32C50SU

FRONT PANEL COLOUR BLACK SILVER

DIGITAL VNR

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

SUPER DIGIPURE

This function uses the latest in digital technology to give you a natural-looking picture.

MOVIE THEATRE

This function displays a cinema film picture more smoothly and naturally on the screen.

3D CINEMA SOUND

You can enjoy sounds with a widerambience.

2.3 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

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

C : 300mV

(P-P)

, 75Ω Used Used

(B-W)

Used Used

(SCL2 / TV-LINK)

, 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

Used (R) Used (C2/R)

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

[Pin assignment]

20 18 16 14 12 10 8 6 4 2

1-6 (No.YA204)

21 19 17 15 13 11 9 7 5 3 1

2.4 TECHNICAL INFORMATION

2.4.1 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.

2.4.1.1 SPECIFICATIONS

The following table shows the specifications of this unit.

Item Specifications Remarks

Maximum dimensions ( W × H × D ) 761mm × 451mm × 51mm

Weight 8.0kg

Effective screen size Diagonal: 800.4mm (H:697.7mm × V : 392.3mm) 32V type

Aspect ratio 16 : 9

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

Resolution Horizontally 1366 × Vertically 768 × RGB <W-XGA> 3147264 dots in total

Pixel pitch (pixel size) Horizontally:0.51075mm, Vertically:0.51075mm

Displayed colour 16777216 colours 256 colours for R, G, and B

Brightness 500cd/m

Contrast ratio 1000: 1

Response time 8ms

View angle Horizontally: 170°, Vertically: 170°

Surface polarizer Anti-Glare type, Low reflective coat

Colour filter Vertical stripe

Backlight Dyrect-type Cold cathode fluorescent lamp × 16

Power supply voltage in LCD 6.5V

Power supply voltage in inverter 18V

Panel interface system LVDS (Low Voltage Differential Signaling)

2.4.1.2 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 colour 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 colour and find out the cell that is flashing on and off.

(No.YA204)1-7

2.4.2 MAIN CPU PIN FUNCTION [IC7501 : DIGITAL SIGNAL PWB ASS'Y]

Pin Pin name I/O Function Pin Pin name I/O Function

1 TCK I Test purpose 65 D2 I/O Program ROM data for main CPU 2 TMS I Test purpose 66 D12 I/O Program ROM data for main CPU 3 TDI I Test purpose 67 D10 I/O Program ROM data for main CPU 4 TDO O Test purpose 68 VSS33 - GND 5 P2.8 O Not used 69 VDD33 I 3.3V 6 P2.9 O Blue for OSD 70 D4 I/O Program ROM data for main CPU 7 P2.10 O Blue for OSD 71 D3 I/O Program ROM data for main CPU 8 P2.11 O Blue for OSD 72 D11 I/O Program ROM data for main CPU

9 P2.12 O Blue for OSD 73 RSTIN I Reset 10 P2.13 O Blue for OSD 74 POWER O Sleep state release for chassis CPU [Relese : L] 11 P2.14 I Not used 75 P3.1 O Not used 12 P2.15 O Request for chassis CPU communication 76 REMOCON I Remote control 13 VSS33 - GND 77 P3.3 I Clock for OSD 14 VDD33 I 3.3V 78 P3.4 O Red for OSD 15 P4.5 O Not used 79 P3.5 O Red for OSD 16 A20 O Program ROM address for main CPU 80 P3.6 O Red for OSD 17 A19 O Program ROM address for main CPU 81 P3.7 O Red for OSD 18 A18 O Program ROM address for main CPU 82 MTST O Data transmission for chassis CPU communication 19 A17 O Program ROM address for main CPU 83 MTSR I Data receive for chassis CPU communication 20 VSS25 - GND 84 VSS33 - GND 21 VDD25 I 2.5V 85 VDD33 I 3.3V 22 A16 O Program ROM address for main CPU 86 VSS25 - GND 23 A8 O Program ROM address for main CPU 87 VDD25 I 2.5V 24 A7 O Program ROM address for main CPU 88 TXD0 O Communication for adjustment 25 A9 O Program ROM address for main CPU 89 RXD0 O Communication for adjustment 26 A6 O Program ROM address for main CPU 90 P3.12 O Red for OSD 27 A5 O Program ROM address for main CPU 91 CLK O Clock for chassis CPU communication 28 A10 O Program ROM address for main CPU 92 P3.15 O Green for OSD 29 A11 O Program ROM address for main CPU 93 P5.14 O Green for OSD 30 A12 O Program ROM address for main CPU 94 P5.15 O Green for OSD 31 VSS33 - GND 95 TRIG_IN O Green for OSD 32 VDD33 I 3.3V 96 TRIG_OUT O Green for OSD 33 A4 O Program ROM address for main CPU 97 P6.2 O Green for OSD 34 A3 O Program ROM address for main CPU 98 P6.3 O I 35 A2 O Program ROM address for main CPU 99 P6.4 I/O I 36 A1 O Program ROM address for main CPU 100 P6.5 O Teletext signal select [Analog RGB : H / Digital RGB : L] 37 A0 O Program ROM address for main CPU 101 IRQ O Not used 38 A13 O Program ROM address for main CPU 102 VSYNC I Vertical sync 39 ARAS/A14 O Program ROM address for main CPU 103 HSYNC I Horizontal sync 40 CAS/A15 O Program ROM address for main CPU 104 41 VSS33 - GND 105 BLANK O Ys for OSD / Teletext 42 VDD33 I 3.3V 106 VDD33 I 3.3V 43 MEMCLK O Clock for memory 107 VSS33 - GND 44 CSSDRAM O Chip select for memory 108 XTAL1 I 6MHz for system clock 45 CLKEN O Clock enable for memory 109 XTAL2 O 6MHz for system clock 46 CSROM O Chip select for memory 110 VSSA - GND 47 RD O Read for memory 111 VDDA I 2.5V 48 UDQM O Control buffer of memory 112 R O R for OSD / Teletext 49 LDQM O Control buffer of memory 113 G O G for OSD / Teletext 50 WR O Write for memory 114 B O B for OSD / Teletext 51 D15 I/O Program ROM data for main CPU 115 VSSA - GND 52 VSS33 - GND 116 VDDA I 2.5V 53 VDD33 I 3.3V 117 CVBS2 I Video for Teletext 54 D7 I/O Program ROM data for main CPU 118 VSSA - GND 55 D0 I/O Program ROM data for main CPU 119 VDDA I 2.5V 56 D14 I/O Program ROM data for main CPU 120 CVBS1B I Video for Teletext 57 D8 I/O Program ROM data for main CPU 121 CVBS1A I Video for Teletext 58 D6 I/O Program ROM data for main CPU 122 VSSA - GND 59 D1 I/O Program ROM data for main CPU 123 VDDA I 2.5V 60 VSS33 - GND 124 KEY1 I Key scan data 1 [ON : H] 61 VDD33 I 3.3V 125 KEY2 I Key scan data 2 [ON : H] 62 D13 I/O Program ROM data for main CPU 126 MECA_SW I Main power ON / OFF control [ON : L] 63 D9 I/O Program ROM data for main CPU 127 P5.3 I Not used 64 D5 I/O Program ROM data for main CPU 128 TMODE I Test purpose

COR/RSTOUT

C bus clock (for main memory)

C bus Data (for main memory)

O Not used

1-8 (No.YA204)

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