NORCENT LT-2722 Schematic

Norcent LT2722

VII

LCD TV MONITOR

THESE DOCUMENTS ARE FOR REPAIR SERVICE INFORMATION ONLY. EVERY REASONABLE EFFORT HAS BEEN MADE TO ENSURE THE ACCURACY OF THIS MANUAL; WE CANNOT GUARANTEE THE ACCURACY OF THIS INFORMATION AFTER THE DATE OF PUBLICATION AND DISCLAIMS RELIABILITY FOR CHANGES, ERRORS OR OMISSIONS.

Norcent LT2722

Revision List

Version Release Date Revision History Model Name

A00 Jan.-09-2006 Initial Release EF84MGNKB2NCTMC

Norcent LT2722

Table Of Contents

Revision List .............…………...............……..............................................…………........................... 1

Table Of Contents .............................................................................................………….......................... 2

1. General Specifications ................................................................................………….......................... 3

2. Operating Instructions ..................................................................................……………..………….. 4

2.1 The Use Of Remote Control ..........................................................................................…………… 4

2.2 Front Panel Control Knobs ..........................................................................................…………… 5

2.3 OSD Operating ............................................................................................................…………… 5

2.4 Safety Notice ............ ...................................................................................................…………...…. 10

3. Input Specification ..........................................................................................……………………… 13

3.1 Input Signal connector ............................................................................................................... 13

3.2 Factory Preset Display Modes............................................................................................................ 14

4. Mechanical Instructions ........……………………………………………………………………………. 15

5. Repair Flow Chart ...................................................................................................................... 21

6. White Balance, Luminance Adjustment …………………………………………………………………. 26

7. BOM List ........................................................…………………………………………......................... 28

8. PCB Layout ........................………………………………………...........................………………...…. 51

8.1 Main Board ......................……....................................................…………………………………. 51

8.2 Power Board ...................……....................................................…………………………………. 55

8.3 Key/IR Board ...................…………..........................................………………………………….. 57

8.4 Earphone Board ..........................…………........................................……………………………….. 58

9. Block Diagram .........................................................................................…………………………...... 59

9.1 Main Board ...........................………........……………………………………………………………..... 59

9.2 Power Board ...................................………………………………………………………...………..... 60

9.3 Exploded View ...........................………………………………………………………………………. 61

10. Schematic Diagram .............…………....................................................…………………………… 62

10.1 Main Board ......................……....................................................………………………………… 62

10.2 Power Board ...................……....................................................………………………………… 74

10.3 Key/ IR Board ..........................…………........................................……………………………….. 76

1. General Specifications

Norcent LT2722

LCD Panel

TV Function

Items

Screen Size 27” TFT LCD color Panel (CMO) Aspect Ratio 16:9 Resolution 1280 x 720 (WXGA) Active Display Area H x V 597.12mm x 335.88mm Pixel Pitch 0.4665mm × 0.4665mm Display colors 16.7 million Contrast Ratio 600:1 (Typical) Brightness 550 cd / m² (Typical) Viewing Angle 170°(Horizontal) / 170°(Vertical) Response Time 16.6 ms (Typical) Lamp Lifetime 60,000 hr Color Temperature Cool / Warm (For PC only) TV Tuning System Sound System Color Systems AV1

NTSC 181 Channel (PLL band) electronic adjustment system MTS + SAP NTSC RCA x 1 Audio channel L/R x 1

Specification

Video Inputs

PC Input

Audio Output Audio Output: L / R

OSD language English, French and Spanish (default is English)

Power

Panel Tilt Forwards/Backwards/ Rotation -5° / +20°/ ±35°

AV2

Component HDTV Signal Input Analog: D-Sub 15 pin (detachable cable) PnP compatibility DDC2B

Input frequency Recommended Analog: 1024 x 768 (60Hz)

Input Audio Headphone Mini-jack for stereo (3.5 ø)

Power Supply AC 100V~240V, 50/60 Hz Power Consumption <150 W

Operating Temp. +0°C ~ + 40°C

RCA x 1 S-Video x 1 YCbCr x 1 Audio channel L/R x 1 YPbPr x 1 Audio channel L/R x 1

Analog: FH: 31.5 KHz to 80 KHz

FV: 56 Hz to 75 Hz

Speaker (built-in): Two 5 watt speakers Headphone Mini-jack jack stereo (3.5 ø) Line Output (RCA L/R)

Audio channel L/R x 1 (Shared)

Environment

Dimension W x H x D (with stand) 898 x 500x285(mm) Weight With Stand 13.4Kg

Accessories

Storage Temp. -10°C ~ + 60°C Operating Humidity 10% ~ 85%

D-Sub Signal Cable, AC Power cord, 3.5mm Audio cable, Remote Controller, Battery (x2), User’s manual

2. Operations Instructions

grap

2.1 The Use Of Remote Control

POWER:

Press to turn on/off the TV. The TV is never completely powered off unless it is physically unplugged.

0~9/100 Digit buttons

To select a TV channel.

Press ▲ or▼ to brows through the TV channels which are not erased. To view a blocked channel, use the digit buttons to access the channel and enter

our access code.

VOL Press + or – to adjust the volume.

SIZE Display the graphic in 16:9 or 4:3 mode

SLEEP

With this key you can set a time period after which the TV should switch itself to standby. Press the ke repeatedly to select the number of minutes. The counter runs from 0, 30, 60, 120 minutes. The time begins to count down from the number of minutes selected after the display has disappeared.

PIP ON/OFF

Used to switch the PIP function ON or OFF

PIP/POP Press this button to display PC input and other input on the screen at the same time

MENU, ▲, ▼, ◄, ► These buttons are used to display or adjust the various functionalities.When the PIP is ON but no menus are available, use these ▲, ▼, ◄, ► to change the position of the PIP.

V-CHIP

Use this button to define the movies that this TV set can receive

SWAP

Press to swap the two screens when PIP o POP is work

Norcent LT2722

MUTE

Temporarily interrupt the sound or restore it.

DISPLAY

Press this button to Display Channel number on the right-top

MTS

Press this key to activate Multichannel Television Sound, Stereo or Mono sound.

PRE-CH

To display the previousl selected TV channel.

TV/VIDEO

Select your input source: press TV/VIDEO and ▲, ▼, ◄, ► to select TV ,S-VIDEO, AV1, AV2, COMPONENT,VGA(PC) or HDTV mode, according to where you connected your external source. AV1/AV2 for a VCR connected

to the AV connectors of the TV.

 S-VIDEO for a S-Video VCR

connected to the S-VIDEO connector of the TV.

 COMPONENT and HDTV

input via Y,Cb,Cr / Y,Pb,Pr on the DVD Player or set top box.

VGA For PC mode

CAPTION

Press this button to turn

Closed Ca

PIP TV/VIDEO

Select the signal source: If you are in main picture or HDTV mode, you can select audio1, audio2, S-video, color contras or TV signal. Otherwise, you can only select computer

hics or HDTV.

tion on.

Norcent LT2722

2.2 Front Panel Control Knobs

Power Key: Press to turn on or off the TV. MENU Key: Press to show the OSD menu and exit OSD menu at the TV. Down / Up Key: Press to perform select function and channel.

- / + Key: Press to confirm your function selection and adjustment. Source Key: Press to select your input source.

2.3 OSD Operations

1. Press the MENU button to display or close the main menu.

2. Use the cursor up/down to select a menu item.

3. Use the cursor left/right to enter a submenu or enable/disable the function.

4. Press the MENU button to exit the menu.

5. Use the instruction bar display under the menu to assist in the operation of this equipment.

MAIN MENU

Press the MENU button into the main OSD (On Screen Display). Adjust item include PICTURE PARAMETERS,

PC PARAMETERS, AUDIO SETTINGS, PICTURE-IN-PICTURE, CHANNEL SETTINGS, PARENTAL CONTROLS and GENERAL SETTINGS.

PICTURE PARAMETERS

BRIGHTNESS: Adjust the brightness of the image. CONTRAST: Adjust the contrast of the image. SATURATION: Adjust the depth of color of the image. HUE: Adjust the red/green hue of the image. COLOR TEMP: Adjust the color temperature to your preference: 5000°, 6500°, 9300°K or select USER R, USER G,

USER B to define your personal settings.

FLESHTONE: The flesh tone is automatically adjusted, rendering a more natural color. SHARPNESS: Adjust the sharpness of the video image for display accordingly.

PC PARAMETERS

Norcent LT2722

AUTO CONFIG: Enable the automatic configuration of the optimum size of the graphic. CLOCK: Adjust the time. PHASE: Adjust the phase of the graphic. POSITION: Adjust the position and angle of the graphic.

AUDIO SETTINGS

BASS: Adjust bass tone. TREBLE: Adjust treble tone. SRS: Switch SRS surround sound ON or OFF.

MTS: Select MONO, STEREO or SAP for bilingual setup.

MUTE: Temporarily mute the sound (can be done through remote control).

Norcent LT2722

PICTURE-IN-PICTURE

PIP POSITION: The PIP can be placed in any position on the screen according to one’s wishes. If there is no

menu, use the ▲, ▼, ◄, ► buttons on the remote control to change the PIP position.

PIP SIZE: Can be used to switch the PIP off (OFF) or select the size (SMALL, MEDIUM, LARGE) of the PIP.

Can also be used to select one of two types (POP, PBP) of dual graphics.

CHANNEL SETTINGS

SYSTEM: Used to choose between (ANTENNA) or (CABLE). CHANNEL EDIT: The auto scan function searches and stores the signal of the TV station when the YES option is

selected. The ADD or DELETE function edits the TV station signal while the channel will be displayed if the CURRENT CH function is selected.

PARENTAL CONTROLS

Norcent LT2722

LOCK MENU: Switch the functionality to configure ratings on or off. MPAA RATING: Configure MPAA ratings. TV PG RATING: Configure TVPG ratings. PASSWORD: Change the password (default is ‘1111”). Please follow the instructions on the screen. Once

changed, please remember your own password. If you have forgotten your password, please do the following: “POWER (OFF)  MENU  V-CHIP  MUTE” to revert to the default password of 1111.

CAPTION

Press the “CAPTION” button on the remote to initiate the functionality list as shown on the left. CC CONTROL: Switch the subtitles function ON or OFF.

MODE: Select mode of subtitles. DISPLAY: Select display of subtitles.

GENERAL SETTINGS

Norcent LT2722

OSD POSITION: Shift the position to one’s preference. OSD TIMEOUT: Configure the time to be displayed on screen. OSD LANGUAGE: Configure the language (English, French or Spanish) for the menu. OSD LOCK: Lock the selected configurations to prevent them from being overwritten. SLEEP TIMER: Configure the time for sleep mode. INFORMATIONS : Display the resolution and H sync, V synch for the main graphic.。 FACTORY RESET: Select YES to revert to default configurations. TRANSPARENCY: Adjust the brightness of the background.

Norcent LT2722

2.4 Safety Notice

For Y our Safety

Before operating the TV please read this manual thoroughly. This manual should be retained for future reference。

FCC Class B Radio Frequency Interference St atement WARNING: (FOR FCC CERTIFIED MODELS)

NOTE: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to

Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, radiate radio frequency energy, and if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

1. Reorient or relocate the receiving antenna.

2. Increase the separation between the equipment and receiver.

3. Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.

4. Consult the dealer or an experienced radio/TV technician for help.

NOTICE

1. The changes or modifications not expressly approved by the party responsible for compliance could void the user's authority to operate the equipment.

2. Shielded interface cables and AC power cord, if any, must be used in order to comply with the emission limits.

WARNING:

To prevent fire or shock hazard, do not expose the TV to rain or moisture. Dangerously high voltages are present inside the TV. Do not open the cabinet. Refer servicing to qualified personnel only.

SRS, SRS and

are registered trademarks of SRS Labs, Inc.

This product is designed using SRS technology with permission from SRS Labs, Inc.

SAFETY: Lamp Disposal

LAMP(S) INSIDE THIS PRODUCT CONTAIN MERCURY AND MUST BE RECYCLED OR DISPOSED OF ACCORDING TO LOCAL, STATE OR FEDERAL LAWS. FOR MORE INFORMATION, CONTACT THE ELECTRONIC INDUSTRIES ALLIANCE AT WWW.EIAE.ORG.

IMPORTANT SAFETY INSTRUCTIONS

Norcent LT2722

Read before operating equipment

1. Read these instructions.

2. Keep these instructions.

3. Heed all warnings.

4. Follow all instructions.

5. Do not use this apparatus near water.

6. Clean only with a dry cloth.

7. Do not block any of the ventilation openings. Install in accordance with the manufacturers instructions.

8. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including

amplifiers) that produce heat.

9. Do not defeat the safety purpose of the polarized or grounding type plug. A polarized plug has two blades with

one wider than the other. A grounding type plug has two blades and third grounding prong. The wide blade or third prong is provided for your safety. When the provided plug does not fit into your outlet, consult an electrician for replacement of the obsolete outlet.

10. Protect the power cord from being walked on or pinched particularly at plugs, convenience receptacles, and the

point where they exit from the apparatus.

11. Only use attachments/accessories specified by the manufacturer.

12. Use only with a cart, stand, tripod, bracket, or table specified by the manufacturer, or sold with the apparatus.

When a cart is used, use caution when moving the cart/apparatus combination to avoid injury from tip-over.

13. The TV should be operated only from the type of power source indicated on the label. If you are not sure of the

type of power supplied to your home, consult your dealer or local power company.

14. Unplug this apparatus during lightning storms or when unused for long periods of time.

15. Refer all servicing to qualified service personnel. Servicing is required when the apparatus has been damaged

in any way, such as power-supply cord or plug is damaged, liquid has been spilled or objects have fallen into apparatus, the apparatus has been exposed to rain or moisture, does not operate normally, or has been dropped.

16. This product may contain lead or mercury. Disposal of these materials may be regulated due to environmental

considerations. For disposal or recycling information, please contact your local authorities or the Electronic Industries Alliance: www.eiae.org

17. Damage Requiring Service – The appliance should be serviced by qualified service personnel when:

A. The power supply cord or the plug has been damaged; or B. Objects have fallen, or liquid has been spilled into the appliance; or C. The appliance has been exposed to rain; or D. The appliance does not appear to operate normally or exhibits a marked change in performance; or

E. The appliance has been dropped, or the enclosure is damaged. Tilt/Stability – All televisions must comply with recommended international global safety standards for tilt and stability properties of its cabinets design. Do not compromise these design standards by applying excessive pull force to the front, or top, of the cabinet, which could ultimately overturn the product. Also, do not endanger yourself, or children, by placing electronic equipment/toys on the top of the cabinet. Such

Norcent LT2722

items could unsuspectingly fall from the top of the set and cause product damage and/or personal injury.

Power Lines – An outdoor antenna should be located away from power lines. Outdoor Antenna Grounding – If an outside antenna is connected to the receiver, be sure the antenna system is

grounded so as to provide some protection against voltage surges and built up static charges. Section 810 of the National Electric Code, ANSI/NFPA No. 70-1984, provides information with respect to proper grounding of the mats and supporting structure grounding of the lead-in wire to an antenna-discharge unit, size of grounding connectors, location of antenna-discharge unit, connection to grounding electrodes and requirements for the grounding electrode. See Figure below.

EXAMPLE OF ANTENNA GROUNDING AS PER NATIONAL ELECTRICAL CODE Note to the CATV system installer: This reminder is provided to call the CATV system installer ’s attention to Article 820-40 of the NEC that provides guidelines for proper grounding and, in particular, specifies that the cable ground shall be connected to the grounding system of the building, as close to the point of cable entry as practical. Objects and Liquid Entry – Care should be taken so that objects do not fall and liquids are not spilled into the enclosure through openings.

Norcent LT2722

3. Input Specification

3.1 Input Signal connector

This procedure gives you instructions for installing and using the LCD TV display. Lay the display on the desired operation and plug the power cord into a convenient AC outlet. Three-wire power cord must be shielded and is provided as a safety precaution as it connect s the chassi s and ca binet to the electri ca l conduct ground. If the AC outlet in your location does not have provisions for the grounded type plug, the installer should attach the proper adapter to ensure a safe ground potential.

Connect the 15-pin D-SUB color display shielded signal cable to your sign al system device a nd lock both screws on the connector to ensure firm grounding. The connector information is as follow:

11 15

15 - Pin Color Display Signal Cable

Pin No. Description Pin No. Description

1. Red Video 9. No Pin

2. Green Video 10. Sync Ground

3. Blue Video 11. Not Used

4. Not Used 12. Serial Data for DDC

5. Ground 13. Horiz. Sync

6. Ground-R 14. Vert. Sync

7. Ground-G 15. Serial Clock for DDC

8. Ground-B

Apply power to the display by turning the power switch to the "ON" position and allow about te n secon ds for Pane l warm-up. The Power-On indicator lights "GREEN" when the display is on.

With proper signals feed to the display, a pattern or data should appear on the screen, adjust the brightness and contrast to the most pleasing display, or press auto-adjust to get the best picture-quality.

This TV (with PC function) has power saving function following the VESA DPMS. Be sure to connect the signal cable to the PC.

If your TV requires service, it must be returned with the power cord.

3.2 Factory Preset Display Modes:

Horizontal Vertical

Resolution

720x400 31.5 N 70.1 P 640x480 31.5 N 59.9 N 640x480 37.9 N 72.8 N 640x480 37.5 N 75 N 800x600 37.9 P 60.3 P 800x600 48.1 P 72.2 P 800x600 46.9 P 75 P

1024x768 48.3 N 60 N

1280x1024 80 P 75 P

Frequency

Nominal

(KHz)

VGA MODES

Sync

Polarity

Nominal

Freq.

(Hz)

Norcent LT2722

Sync

Polarity

Norcent LT2722

4. Mechanical Instructions

Step Figure Description

Lay the LCD-TV

Preparation

on a flat, soft and clean surface.

Remove hinge cover

Remove base

Remove the hinge cover as the arrowheads.

Remove the six screws

Norcent LT2722

Remove cover cable

Remove back cover

Push the clip as the arrowheads

Remove the six screws

Remove cover chin

Remove the six

screws

Norcent LT2722

Remove shield

Remove the total six screws

Remove main board

Remove the four scres and disconnect he wire harnesses

Norcent LT2722

Remove power board

Remove main frame

Remove the six screws and disconnect the wire harness

Remove the fourteen screws

Remove speakers and bezel

Remove the sixteen screws(the left and right two speakers)

Norcent LT2722

Remove panel

Remove the four screws

Norcent LT2722

The end

Remove the four screws

5. Repair Flow Chart

(

)

Panel Control Circuit

Check CN605 pin 19-22 is 5V and signal on pin 3,4,6,7,9,10,12,13,15,16

NO 5V

Check Q401, Q400

relative circuit

Replace Q401, Q400

No Display

NO Si

Check U403 crystal

14.318MHZ

X400

Check power supply for

1.8V, 2.5V, and 3.3V

Replace U403

Norcent LT2722

Replace panel or FPC cable to panel

nal

Replace X400

Check relative circuit

Main Board Power Circuit

(

)

No Power

Check CN606 Pin 3, 4(12V), Pin 5, 6 (5V)

Check U701 input (5V), U706 input (12V)

U704 Pin2

U700 Pin2

(1.8V)

U705 Pin2

Norcent LT2722

Check Power Board circuit

Check Q701, Q702 and PWR_ON control relative circuit

U701/U702/U703/U 704 Pin2

2.5V

Remote Control Block

Remote Control can’t work

Check IR Board J1 Pin 1,4(5V) and voltage at Pin 3 will change when received signal

Check Main board 5V power relative circuit and signal on LP602

Check Power relative circuit

Key Board Control Block

Press key no function

Check CN600 Pin6, 7, 8 voltage will change when key

ressed

Check line between keyboard and main board or U403

Check U403 and relative circuit

Norcent LT2722

Replace D600 or IR board

Replace line between Main board and IR Board or replace U403

Replace keyboard

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