Firmware Download

Category: LCD Monitor Repair and Service 

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LENOVO L2062bW 

SERVICE MODE

Factory mode adjustment
After replacing the Main board and the Panel, Check for enter the Factory mode ,then re-writing DDC is necessary.
Press MENU button and hold,reinsert the Power cord , then ,press MENU , the monitor will may enter Factory OSD Menu. Then Press . Factory OSD Menu will appear in the screen.

In normal user mode, open the menu to restore factory default values

Maintenance

Maintainability Requirement
1. Voltmeter. & digital multimeter
2. Oscilloscope.
3. Pattern Generator.
4. DDC Tool with Compatible Computer.
5. Alignment Tool.
6. LCD Color Analyzer.
7. Service Manual.
8. User Manual.
9. repair tools etc

Disassembly SOP
1. Precaution
Please read the precautions as follows to prevent any damages to the LCD Monitor
Make sure all power connection is removed. Be sure that the LCD Monitor is in power off status.

1.Prepare soft cloth and sponge as working platform to place LCD monitor horizontally.

2. Hold LCD by the side carefully and DON’T touch or press panel directly.

3. appropriate tools
select the appropriate tools for disassembly and re-assembly.

Phillips screwdriver
spacer screwdriver
C/D Disassembly Tool
Gloves or soft cloth

Software update step
After replacing the Main board and the Panel, Check if white-balance is within the specs ,then re-writing DDC is necessary.
Software information

U401	056G1125191	IC RTD2122L-LF LQFP-48
SMTCR-U401	100GLRSA006B11	L2021W_SEC_LTM200KT03_M20_ RTD2545LH_100729_v0.01_Eng.H00
U501	056G 562201	IC RTD2545LH-GR QFN-48
	CBPCARJG1J1	G3327-1-X-X-2-090407 FOR L2021WA

Step1： Connection
1. Connect USB cable to the PC USB port and the ISP tool,（ 715GT089-B）；
2. Will be the Monitor VGA cable to connect ISP tool ；
3. ISP tool card connection 

Step2： Installing driver software
1.To install the USB driver software, mstar ISP Driver3-DB07-6-XP-driver

Step3： Run software “RTD Tool V1.7 version”

1.selected ISP,-àRTD2122 ,as shown in, Press the icon to select,Note save HDCP key:

2.selcted “Page Select”

3.Click “64K”,selcted software files

In this way, Automatic Identification space size,Next ,selected “Externd True Size”

4.Click Program icon ,Programming started,After Programming, Appear PASS.

Writing DDC program step
1. Prepared the PC with Windows XP system, DDC recording device (12V)
2. Connect the DDC recording device and the PC through PC parallel port
3. setup “Port95nt” driver program to PC ,
4. select relevant program and run it,
5, Press “LoadFile”, select EDID -model of product, and select input port;
6. key in SN,and other informatiom, key-press “Pragram” button;

LD7552 PWM Controller

Description
The LD7552 is a low cost, low startup current, current mode PWM controller with green-mode power-saving operation. The integrated functions such as the leading-edge blanking of the current sensing, internal slope compensation and the small package provide the users a high efficiency, minimum external component counts, and low cost solution for AC/DC power applications.
The special green-mode control does not only achieve low power consumption but also offer a non-audible-noise operation when the LD7552 operates under light load or no load condition.
The LD7552 is designed for the switching adaptor with 30W> 60W output. The LD7552 is offered in both SOP-8 and DIP-8 package.

PIN CONFIGURATION

1 GND - Ground
2 COMP - Voltage feedback pin (same as the COMP pin in UC384X), By connecting a photo-coupler to close the control loop and achieve the regulation.
3 VCC  - Supply voltage pin
4 RT - This pin is to program the switching frequency. By connecting a resistor to ground to set the switching frequency.
5 NC - Unconnected pin
6 CS - Current sense pin, connect to sense the MOSFET current
7 VCC - Supply voltage pin
8 OUT - Gate drive output to drive the external MOSFET

POWER SUPPLY SCHEMATIC 

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Category: LCD Television Repair and Service 

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ENVISION EN7220

SERVICE MODE

How to access to service mode

Press MENU button during 2 seconds along with press Power button will activate the factory mode, then MCU will do AUTO LEVEL automatically. Meanwhile press MENU the OSD screen will located at left top of panel

White-Balance, Luminance adjustment
Approximately 30 minutes should be allowed for warm up before proceeding white balance adjustment.  

Before started adjust white balance ,please setting the Chroma-7120 MEM. channel 1 to 6500 color, MEM. channel 2 to 7800 color ( our 6500 parameter is x = 313 ±10, y = 329 ±10, Y = 200 ±10 cd/m2 , 7200 parameter is x = 296 ±10, y = 311 ±10, Y = 200 ±10 cd/m2)

How to setting MEM.channel you can reference to chroma 7120 user guide or simple use “ SC” key and “ NEXT” key to modify xyY value and use “ID” key to modify the TEXT description Following is the procedure to do white-balance adjust

Press MENU button during 2 seconds along with press Power button will activate the factory mode, then MCU will do AUTO LEVEL automatically. Meanwhile press MENU the OSD screen will located at left top of panel.
I. Bias adjustment :

1. Set the contrast to 70.

2. Sdjust the Brightness to 90.
II. Gain adjustment :

Move cursor to “-Factory-” and press MENU key

a. Adjust 6500 color-temperature

1. Switch the chroma-7120 to RGB-mode (with press “MODE” button )

2. switch the MEM. Channel to Channel 01 ( with up or down arrow on chroma 7120 )

3. The LCD-indicator on chroma 7120 will show x = 313 ±10, y = 329 ±10, Y = 200 ±5 cd/m2

4. Adjust the RED on OSD window until chroma 7120 indicator reached the value R=100

5. adjust the GREEN on OSD, until chroma 7120 indicator reached G=100

6. adjust the BLUE on OSD, until chroma 7120 indicator reached B=100

7. repeat above procedure ( item 5,6,7) until chroma 7120 RGB value meet the tolerance =100±2

8. Press Exit on OSD window to save the adjustment result

b. Adjust 7800 color-temperature

9. Switch the chroma-7120 to RGB-mode (with press “MODE” button )

10. switch the MEM.channel to Channel 02 ( with up or down arrow on chroma 7120 )

11. The LCD-indicator on chroma 7120 will show x = 296 ±10, y = 311 ±10, Y = 200 ±5 cd/m2

12. Adjust the RED on OSD window until chroma 7120 indicator reached the value R=100

13. adjust the GREEN on OSD, until chroma 7120 indicator reached G=100

14. adjust the BLUE on OSD, until chroma 7120 indicator reached B=100

15. repeat above procedure ( item 5,6,7) until chroma 7120 RGB value meet the tolerance =100±2

16. Press Exit on OSD window to save the adjustment result Turn the POWER-button off to on to quit from factory mode.

SG6841 PWM Controller

DESCRIPTION
This highly integrated PWM controllers, SG6841 series, provides several features to enhance the performance of low power flyback converters. To minimize standby power consumption, the proprietary green-mode function provides off-time modulation to linearly decrease the switching frequency under light-load conditions. This green-mode function assists the power supply to easily meet the power conservation requirement. Due to BiCMOS process, the start-up current and operation current is reduced to 30uA and 3mA, respectively, to improve power conversion efficiency. Large start-up resistance can be used for further power saving. Built-in synchronized slope compensation ensures the stability of peak current mode control. A proprietary internal compensation ensures constant output power limit for universal AC input voltage from 90VAC to 264VAC. SG6841 provides many protection functions. Pulse by pulse current limit ensures a constant output current under short circuit. If a short circuit failure or over load happens, the SG6841 will shut off after a continuous high voltage detection on FB pin. The gate output is clamped at 18V to protect the power MOS from over voltage damage. An external NTC thermistor can be applied to sense the ambient temperature for over-temperature protection. The SG6841 series are available in 8-pin DIP and SO packages.

1 GND - Ground Ground.
2 FB  - Feedback -  The signal from external compensation circuit is feed into this pin. The PWM duty cycle is determined by this FB pin and current sense signal from Pin 6.
3 VIN - Start-Up - This pin is pulled high to the rectified line input through a resistor for start-up. Since the start-up current requirement for SG6841 is very small, a large start-up resistance can be used to minimize power loss. Under normal operation, this pin is also used to detect line voltage to compensate for constant output power limit for universal AC input.
4 Ri - Reference Setting - A resistor from RI pin to ground will generate a constant current source forSG6841. This current is used to charge an internal capacitor and hence the switching frequency are determined. Increasing the resistance will decrease the current source and reduce the switching frequency. A 26kΩ resistor Ri creates a 50uA constant current Ii and generates 65kHz switching frequency.
5 RT -  Temperature Protection -  For over-temperature protection. An external NTC thermistor is connected from this pin to ground. The impedance of the NTC will decrease under high temperature. Once the voltage on RT pin drops below a fixed limit, the PWM output will be disabled.
6 SENSE - Current Sense -  Current sense. The sensed voltage is used for current mode control and pulse-by-pulse current limiting.
7 VDD  - Power supply  - Power Supply.
8 GATE  - Driver Output -  The totem-pole output driver for the power MOSFET. A soft driving waveform is implemented to improve EMI.

TL1451 LINEAR INTEGRATED CIRCUIT

DESCRIPTION
The UTC TL1451 incorporates on a single monolithic chip all the functions required in the construction of two pulse-width-modulation (PWM) control circuits. Designed primarily for power supply control, the UTC TL1451 contains an on-chip 2.5V regulator, two error amplifiers, an adjustable oscillator, two dead-time comparators, undervoltage lockout circuitry, and dual common –emitter output transistor circuits.

POWER SUPPLY CIRCUIT 

BACK LIGHT INVERTER CIRCUIT 

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Category: LCD Monitor Repair and Service 

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DELL 1907FPc 

SERVICE MODE

Enter into factory mode
Press MENU and up button at the same time, during press power button on will activate the factory mode, then press MENU again, main MENU will be in the middle of the screen.

White balance, Luminance adjustment
Approximately 30 minutes should be allowed for warm up before proceeding White-Balance adjustment.
Before started adjust white balance, please setting the Chroma-7120 MEM. Channel 3 to 65000K colors, MEM. Channel 4 to 93000K colors, MEM. Channel 9 to 57000K (our 9300 parameter is x=283±28, y=297±28, Y = 200 ±20 cd/m2, 6500 parameter is x =313±28, y=329±28, Y = 230 ±20 cd/m2, and 5700 parameter is x = 328 ±28, y = 344 ±28, Y = 230 ±20 cd/m2)
How to setting MEM.channel you can reference to chroma 7120 user guide or simple use “ SC” key and “ NEXT” key to modify x, y, Y value and use “ID” key to modify the TEXT description Following is the procedure to do white-balance adjust.
Enter into factory mode:
Press MENU and up button at the same time, during press power button on will activate the factory mode, then press MENU again, main MENU will be in the middle of the screen. Gain adjustment:
Move to “Factory Reset” and press MENU key to enter this sub-menu.
Move to “ Factory” and press MENU key.
Move to “ Auto Color” and press MENU key to adjust Gain and Offset automatically;
a. Adjust sRGB (65000K) color-temperature
1. Switch the chroma-7120 to RGB-mode (with press “MODE” button)
2. Switch the MEM.channel to Channel 3 (with up or down arrow on chroma 7120)
3. The LCD-indicator on chroma 7120 will show x =313±28, y=329±28, Y = 230 ±20 cd/m2
4. Adjust the RED on OSD window until chroma 7120 indicator reached the value R=100
5. Adjust the GREEN on OSD, until chroma 7120 indicator reached G=100
6. Adjust the BLUE on OSD, until chroma 7120 indicator reached B=100
7. Repeat above procedure (item 5,6,7) until chroma 7120 RGB value meet the tolerance =100±2
b. Adjust Color1 (93000K) color-temperature
8. Switch the chroma-7120 to RGB-mode (with press “MODE” button)
9. Switch the MEM.channel to Channel 4 (with up or down arrow on chroma 7120)
10. The LCD-indicator on chroma 7120 will show x=283±28, y=297±28, Y = 200 ±20 cd/m2
11. Adjust the RED on OSD window until chroma 7120 indicator reached the value R=100
12. Adjust the GREEN on OSD, until chroma 7120 indicator reached G=100
13. Adjust the BLUE on OSD, until chroma 7120 indicator reached B=100
14. Repeat above procedure (item 5,6,7) until chroma 7120 RGB value meet the tolerance =100±2
c. Adjust Color2 (57000K) color-temperature
15. Switch the chroma-7120 to RGB-mode (with press “MODE” button)
16. Switch the MEM.channel to Channel 9 (with up or down arrow on chroma 7120)
17. The LCD-indicator on chroma 7120 will show x = 328 ±28, y = 344 ±28, Y = 230 ±20 cd/m2

18. Adjust the RED on OSD window until chroma 7120 indicator reached the value R=100
19. Adjust the GREEN on OSD, until chroma 7120 indicator reached G=100
20. Adjust the BLUE on OSD, until chroma 7120 indicator reached B=100
21. Repeat above procedure (item 5,6,7) until chroma 7120 RGB value meet the tolerance =100±2
22. Move cursor to “ Exit/Save” sub-menu and press MENU key to save adjust value and exit.
Turn the POWER-button off to on to quit from factory mode.
Max Brightness measurement
a. Switch to the full white pattern, in user mode main menu:
1. Set <Color Settings> Red, Green, and Blue to the max.
2. Set <Brightness> Brightness, Contrast to the max.
b. The Minimum brightness is 200cd/m2 ±20.

1) After replacing LCD Main board and panel, Check if white-balance is within the specs, then re-writing DDC is necessary.
The white-balance value for each common color temperature:
9300 parameter is x=283±28, y=297±28, Y = 180 ±10 cd/m2,
6500 parameter is x =313±28, y=329±28, Y = 180 ±10 cd/m2,
5700 parameter is x = 328 ±28, y = 344 ±28, Y = 180 ±10 cd/m2)
The color temperature value above must be up to the situation of x<y. The value of Y should be confirmed according to different customers. 15” LCD is commonly 180±20cd/cm2 Center and 17” LCD is required to be larger than 200cd/cm2 (Center). The exact brightness values are confirmed by the checking-regulations of different customers and different models.
2) Steps of white-balance adjustment for LCD:(Take 17” AOC LCD LM724 for example)
1. Required instruments: Chroma7120 Chroma2325 BGA265A）。
2. First connect the instruments together and turn on the LCD power, then warm up for 30 minutes under full white screen mode. First press the “Reset” key in the menu to recover factory set as following.

Set Chroma2325 at round-windows mode and make the detecting-head of Chroma7120 aim at the cross in the middle, the distance between the detecting-head and the cross is 20cm.
3. Set Chroma2325 BGA265A to be T144 1280*1024/60HZ and P105 of full white screen. Test if the
white-balance value is within the specs. Please follow the steps below to adjust if it is beyond the specs.
4. Cut the power. Then press MENU key and re-plug power cable at the same time to enter into the factory mode.

5. Test white-balance again after Auto Level. Adjustment with hand is necessary if it is beyond the specs.
6. Select 7x00 item to adjust cool color-temperature and select 6x00 to adjust warm color- temperature. It can reach to the best effect through adjusting R/G/B value if it inclines to green or blue.

7. Select Exit to the upper menu after completing the adjustment. Then press POWER OFF to exit and save it.
3) Steps for writing DDC：
1. Employ PC, and connect the DDC-writing instrument and the instrument that is ready for writing into DDC to the power of 12V. Connect the signal cable of the latter to D-USB or DVI of DDC-writing instrument (The data-writing of monitor needs transfer-interface) and link the DDC-writing instrument with PC through printer interface.

2. Seek the document with the expanded name of .BAT in DDC file of this model. It appears the indication of “Input Serial No.：＂after dual-click the document to be ready for DDC-writing.
3. Input the serial number of the product (For instance: AOC LM725 is 13 bits), and then press ENTER to start writing
4. Check the indication of DDC-writing program at the end. When you see the picture as the schematic picture above, the“Data compare OK!” Means being written well and that’s the end. Please check if the Manufacturer Name, Vendor Assigned Code, Monitor Name, Serial Number, Week of Manufacture, Year of Manufacture are right. It will appear “Data compare error! ” To indicate failure if the DDC-writing doesn’t perform well. Please check the power resource and the connection of the signal cable, then return to step 3 by pressing ENTER and re-do it.
5. You can exit the program by pressing Ctrl plus C, and then cut the signal cable and the power.
6. The following picture is taking AOC LM725 EDID for example.

Notes:
1. Make sure the system time of PC is in accordance with the real time before writing.
2. The schematic picture is just as an example for description; the exact content of the DDC is dependent on the serial number of the BARCORD of this model.
3. Data DDC-writing needs a transfer interface.
Instruction DDC-writing needs 4 files:
1. Barcode.txt (Supply Barcode length and flow number)
2. *.EXE (DDC-writing program)
3. WR.bat (Group order file for cycling utilization of *EXE, and dual-click this file when perform DDC-writing)
4. W.dat (The content with 128 bits of DDC)

LD7552 PWM Controller

Description
The LD7552 is a low cost, low startup current, current mode PWM controller with green-mode power-saving operation. The integrated functions such as the leading-edge blanking of the current sensing, internal slope compensation and the small package provide the users a high efficiency, minimum external component counts, and low cost solution for AC/DC power applications.
The special green-mode control does not only achieve low power consumption but also offer a non-audible-noise operation when the LD7552 operates under light load or no load condition.
The LD7552 is designed for the switching adaptor with 30W~60W output. The LD7552 is offered in both SOP-8 and DIP-8 package.

PIN CONFIGURATION

1 GND - Ground
2 COMP - Voltage feedback pin (same as the COMP pin in UC384X), By connecting a photo-coupler to close the control loop and achieve the regulation.
3 VCC Supply voltage pin
4 RT - This pin is to program the switching frequency. By connecting a resistor to ground to set the switching frequency.
5 NC -  Unconnected pin
6 CS -  Current sense pin, connect to sense the MOSFET current
7 VCC -  Supply voltage pin
8 OUT -  Gate drive output to drive the external MOSFET.

POWER SUPPLY CIRCUIT 

BACK LIGHT INVERTER CIRCUIT 

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Category: LCD Monitor Repair and Service 

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DELL W2607C

SERVICE MODE

How to access to service mode

After there is no OSD pictures on screen ,Press Number key 2-4-8-6-MENU—INFO in Remote Control will access into the factory mode.

White Balance, Luminance Adjustment
Approximately 30 minutes should be allowed for warm up before proceeding white balance adjustment.
Before started adjust white balance, please set the Chroma-7120 MEM. Channel 3 to Natural colors, MEM.
Channel 4 to 6500K color, MEM. Channel 9 to 9300K colors and MEM. Channel 10 to 5700K colors (Nature parameter is x =289 ± 30, y = 304 ±30, 6500 parameter is x = 313 ± 30, y = 329 ± 30, 9300 parameter is x = 283 ± 30, y = 297 ± 30,5700 parameter is x = 328 ± 30, y = 344 ± 30), The data of Y of all the mode is PC>300,AV>400,S-Video>400,Component>400cd/m2.
Devices Requirement:
1. Chroma 7120, Chroma 2327.
2. AV/S-Video/Component signal generator
How to setting MEM.channel you can reference to Chroma-7120 user guide or simple use “ SC” key and “ NEXT”
key to modify x, y, Y value and use “ID” key to modify the TEXT description
Following is the procedure to do white-balance adjust
After there is no OSD pictures on screen ,Press Number key 2-4-8-6-MENU—INFO in Remote Control will access into the factory mode.
In the factory mode ,the menu as follows:
5700K RGB
6500K RGB the data is the result of RGB after
9300K RGB W/B adjustment;
NATURAL RGB
NVRAM Init ÆInitial EEPROM
Burn in mode On/OFF
The steps of the PC W/B adjustment as follows:
A. Initial the EEPROM
Press “NVRAM Init: Press OK to start” to initial EEPROM.
Bias (Low luminance) adjustment:
Prepare: ensure the currently mode is PC (VGA)
Press “Auto Balance” button (the image is black and white at the PAT42)
B. Gain adjustment:
1. Switch the chroma-7120 to RGB-mode (with press “MODE” button)
2. Let the signal output the white image (press pattern 105), select one of the color temp (as Natural,6500K,9300K,5700K) and adjust factoty mode window RGB until up to the value Chroma7120 R, G, B=100±3.
3. Select another color temp and follows as item 2.
C.The steps of the AV W/B adjustment as follows:
The steps of AV W/B adjustment as follows:
Gain adjustment:
1. Switch the chroma-7120 to RGB-mode (with press “MODE” button)
2. Let the signal output the white image (press pattern 105), select one of the color temp (as Natural,6500K,9300K,5700K) and adjust factoty mode window RGB until up to the value Chroma7120 R, G, B=100±3.
3. Select another color temp and follows as item 2.
D.The steps of the SV(S-Video) W/B adjustment as follows:
The steps of SV’s W/B adjustment is the same as AV’s.
E.The steps of the CP(component) W/B adjustment as follows:
The steps of CP’s W/B adjustment as same as PC’s.
Press MENU button to quit from factory mode.

Max Brightness measurement:
a. Switch to the full white pattern, in normal mode main menu:
Set <Picture Settings> menu Brightness, Contrast to the max.
b. The Minimum brightness is 400cd/m².

STR-W6252D PWM Switching Regulators

Description
The STR-W6200D series are current-mode PWM ICs that incorporate controller chips. These devices are manufactured using a proprietary high-voltage BCD process, and avalancheguaranteed MOSFETs. These elements allow power supply systems designs that are highly reliable and simple, with fewer peripheral components. These ICs also provide Auto-Burst mode operation, which lowers input power requirements at light loads, and improves efficiency over the entire load range and universal-input range.
Applicatons include:
# TV set top box
# LCD PC monitor, LCD TV
# Printer, scanner
# General consumer, PC, and industrial applications requiring SMPS power supply with standby mode

PIN COFIGURATION

1 D/ST - Drain/startup terminal. MOSFET drain and input of start-up signal
2 NC -  Clipped. No connection
3 S/OCP - Source/Overcurrent Protection terminal. MOSFET source and input of overcurrent detection signal
4 VCC Power supply terminal Input of power supply for control circuit
5 GND - Ground terminal Ground
6 FB Feedback terminal - Input of constant voltage control signal
7 FM/ELP -  Frequency jittering and External Latch Protection terminal. Control input for frequency jittering control, and External Latch Protection.

FA5500AP Power Supply Control

Description
FA5500A/FA5501A are control ICs for a power factor correction converter using critical conduction mode of operation. This IC uses a CMOS device with high dielectric strength (30V) to implement low power consumption. These ICs contain compensated current sense comparator for light load and open/short protection at feedback (FB) pin. Compensated current sense comparator for light load keeps output voltage constant from no-load to full-load. Open/short protection at FB pin stops output pulses when voltage divider to detect output voltage becomes fault.

PIN COFIGURATION

1 FB - Voltage Feedback Input. Input for monitoring PFC output voltage
2 COMP – Compensation. Output of error amplifier
3 MUL -  Multiplier Input. Input of multiplier for monitoring sinusoidal waveform
4 IS  - Current Sense Input. Input for sensing MOSFET current signal
5 ZCD - Zero Current Detect Input. Input for detecting that the inductor current reaches zero
6 GND - Ground Ground
7 OUT – Output. Output for direct driving a power MOSFET
8 VCC - Power Supply. Power supply for IC

POWER SUPPLY CIRCUIT 

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Category: LCD monitor Repair and Service 

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ViewSonic VX2235 

Mstar ISP Tool

Setp1: Take the cable of Print Port to connect Print Port of PC and Print Port of fixture(and EDID burn in the same fixture) to connect VGA Cable between D-sub of fixture and D-sub of AD Board of monitor,the monitor must be turned on the power.

Step 2 : Open ISP Tool V4.3.4

Step 3 : Press ”connect” into ISP mode,display the model of Flash,The dialog of figure is displayed “Device Type is Pm25LV512” then press ”Confirm”.

Step 4: Press ”Read” then enter,then press READ to down load the program of BIOS (*.bin).

If down load BIOS that is successful then press ”Confirm”.

Step 5 : Press ”Auto” into below figure that display the value of BIOS Checksum below figure is displayed “0x1626” then press ”Run” to execute the BIOS procedure.

The BIOS procedure is displayed the message ”Verify OK” that the BIOS procedure is successful

Step 6 : Press ”Dis Con” then leave the mode of ISP

Step 7： When select ”ReConnect” and press “Run” then repeat to connect the mode of ISP into next the action of BIOS procedure

Troubleshooting Flow Chart
No power
# Make sure power button (or switch) is ON.
# Make sure A/C power cord is securely connected to the LCD display.
# Plug another electrical device (like a radio) into the power outlet to verify that the outlet is supplying proper voltage.
Power is ON but no screen image
# Make sure the video cable supplied with the LCD display is tightly secured to the video output port on the back of the computer. If the other end of the video cable is not attached permanently to the LCD display, tightly secure it to the LCD display.
# Adjust brightness and contrast.
# If you are using an Macintosh older than G3, you need a Macintosh adapter.
Wrong or abnormal colors
# If any colors (red, green, or blue) are missing, check the video cable to make sure it is securely connected. Loose or broken pins in the cable connector could cause an improper connection.
# Connect the LCD display to another computer.
# If you have an older graphics card, contact ViewSonic® for a non-DDC adapter.
Control buttons do not work
# Press only one button at a time.

STR-W6200D PWM Off-Line Switching Regulator

Description
The STR-W6200D series are power ICs for switching power supplies, incorporating a power MOSFET and a current mode PWM controller IC in one package. Including a startup circuit and a standby function in the controller, the product achieves low power consumption, low standby power, and high cost-effectiveness in power supply systems, while reducing external components.

Applications
Switching power supplies for electronic devices such as:
# White goods
# Consumer electronics
# Office automation
# Industrial equipment
# Communications equipment

PIN CONFIGURATION

1 D/ST - MOSFET drain and input of the startup current
2 – (Pin removed)
3 S/OCP - MOSFET source and input of Overcurrent Protection (OCP) signal
4 VCC - Power supply voltage input for Control Part and input of Overvoltage Protection (OVP) signal
5 GND - Ground
6 FB - Input for constant voltage control signal
7 FM/ELP - Capacitor connection pin for frequency modulation and input of External Latch Protection

POWER SUPPLY SCHEMATIC DIGRAM 

BACK LIGHT INVERTER CIRCUIT 

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                                                Category: LCD Monitor Repair and Service 

DELL W2606C

SERVICE MODE

After there are no OSD pictures on screen ,Press Number key 0000 will into the factory mode, and press Menu key to enter the Factory Mode

White Balance, Luminance Adjustment
Approximately 30 minutes should be allowed for warm up before proceeding white balance adjustment.
Before started adjust white balance, please set the Chroma-7120 MEM. Channel 3 to Natural colors, MEM. Channel 4 to 6500K color, MEM. Channel 9 to 9300K colors and MEM. Channel 10 to 5700K colors (Nature parameter is x =289 ± 15, y = 304 ± 15, 6500 parameter is x = 313 ± 15, y = 329 ± 15, 9300 parameter is x = 283 ± 15, y = 297 ± 15,5700 parameter is x = 328 ± 15, y = 344 ± 15),
The data of Y of all the mode is PC>300,AV>400,S-Video>400,Component>400cd/m2.
How to setting MEM.channel you can reference to Chroma-7120 user guide or simple use “ SC” key and “ NEXT” key to modify x,y,Y value and use “ID” key to modify the TEXT description
Following is the procedure to do white-balance adjust
@ after there are no OSD pictures on screen ,Press Number key 0000 will into the factory mode, and press Menu key to enter the Factory Mode.
@ In the factory mode ,the menu as follows:
5700K RGB
6500K RGB the data is the result of RGB after
9300K RGB W/B adjustment;
NATURAL RGB
Burn In Mode
Auto Balance Auto level adjusts.
Initial NVRAM Initial EEPROM
Boot Power State ON/OFF
The steps of the PC W/B adjustment as follows:
I. Initial the EEPROM
Press “Initial NVRAM” button;
II. Bias (Low luminance) adjustment:
Prepare: ensure the currently mode is PC (VGA)
Press “Auto Balance” button (the image is black and white at the PAT42)
III. Gain adjustment:
1. Switch the chroma-7120 to RGB-mode (with press “MODE” button)
2. Let the signal output the white image (press pattern 105), select one of the color temp (as Natural,6500K,9300K ,5700K) and adjust RGB until up to 100±3.
3. Select another color temp and follows as item 2.
The steps of the AV W/B adjustment as follows:
The steps of AV W/B adjustment as follows:
Gain adjustment:
1. Switch the chroma-7120 to RGB-mode (with press “MODE” button)
2. Let the signal output the white image (press pattern 105), select one of the color temp (as Natural,6500K,9300K,5700K) and adjust RGB until up to 100±3.
3. Select another color temp and follows as item 2.
The steps of the SV(S-Video) W/B adjustment as follows:
The steps of SV’s W/B adjustment is the same as AV’s.
The steps of the CP(component) W/B adjustment as follows:
The steps of CP’s W/B adjustment as same as PC’s.
Max Brightness measurement:
a. Switch to the full white pattern, in normal mode main menu:
Set <Picture Settings> menu Brightness, Contrast to the max.
b. The Minimum brightness is 400cd/m²

Install the software (Gprobe 5.0) for ISP burn in
Operating system
(1) Microsoft windows OS.
(2) 100M free hard-drive space.
(3) 1 free parallel port for DDC2BI communication.

A. Double-click the Install software,

Select the folder where you would like Genesis Gprobe 5 to be installed

Completing the Genesis Gprobe 5 setup wizard,

Note: After finishing the installation, you must restart the PC.

B. Next, installing the Update software,

Completing the update 1 for Genesis Gprobe 5.0 setup wizard,

B. Copy the “ChipDB” folder to the install folder, replace the primary one

Run the program
After the installation, a short-cut icon will appear on your desktop, double click it will run the program.
(1). Select the IC type FL18532-BD (NOTE: If there is not this selection, please check the “ChipDB”),

(2). Open the configure file “isp_flash8_aoc.txt”

Note: When you change the path of the firmware, you must push to save the configure
(3). Click Execute , there will appear the chart

Run the DDC burn in program

(1) Double-click “WinDDC.exe”; it will appear

(2) Click “WriteEDID”, it displays the following textbox. Input the Serial Number printed on the barcode label

(3) The process of DVI DDC burn in is the same to VGA burn in process.

FAN5500 Power Factor Correction

Description
FA5500A/FA5501A are control ICs for a power factor correction converter using critical conduction mode of operation. This IC uses a CMOS device with high dielectric strength (30V) to implement low power consumption. These ICs contain compensated current sense comparator for light load and open/short protection at feedback (FB) pin. Compensated current sense comparator for light load keeps output voltage constant from no-load to full load. Open/short protection at FB pin stops output pulses when voltage divider to detect output voltage becomes fault.
 Features
# Low current consumption by CMOS process
Start-up : 20µA(max.), Operating : 1mA(typ.)
# Drive circuit for connecting a power MOSFET directly
# Output peak current, source : 500mA, sink : 1000mA
# Compensated current sense comparator for light load
# Open/short protection at feedback (FB) pin
# Undervoltage Lockout
FA5500A: 11.5V ON / 9V OFF FA5501A:13V ON / 9V OFF
# Overvoltage protection
# Restart timer
# Package: DIP-8 / SOP-8

PIN CONFIGURATION

1 FB - Voltage Feedback Input Input for monitoring PFC output voltage
2 COMP  -Compensation Output of error amplifier
3 MUL - Multiplier Input Input of multiplier for monitoring sinusoidal waveform
4 IS - Current Sense Input Input for sensing MOSFET current signal
5 ZCD - Zero Current Detect Input Input for detecting that the inductor current reaches zero
6 GND - Ground Ground
7 OUT-  Output Output for direct driving a power MOSFET
8 VCC-  Power Supply Power supply for IC

NCP1377 PWM Current-Mode Controller

Description

The NCP1377 combines a true current mode modulator and a demagnetization detector which ensures full borderline/critical Conduction Mode in any load/line conditions together with minimum drain voltage switching (Quasi−Resonant operation). Due to its inherent skip cycle capability, the controller enters burst mode as soon as the power demand falls below a predetermined level. As this happens at low peak current, no audible noise can be heard. For NCP1377, an internal 8.0 s timer prevents the free−run frequency to exceed 100 kHz (therefore below the 150 kHz CISPR−22 EMI starting limit), while the skip adjustment capability lets the user select the frequency at which the burst foldback takes place. For NC1377B, the internal timer duration is reduced to 3.0 s to allow operation at higher frequencies (up to 300 kHz).

PIN CONFIGURATION

1 Demag  - Core reset detection and OVP. The auxiliary FLYBACK signal ensures discontinuous operation and offers a fixed
overvoltage detection level of 7.2 V.
2 FB -  Sets the peak current setpoint. By connecting an optocoupler to this pin, the peak current setpoint is adjusted
accordingly to the output power demand. By bringing this pin below the internal
skip level, you shut off the device.
3 CS - Current sense input and skip cycle level selection .This pin senses the primary current and routes it to the internal comparator via an L.E.B. By inserting a resistor in series with the pin, you control the level at which the skip operation takes place.
4 - GND The IC ground
5 Drv -  Driving pulses. The driver’s output to an external MOSFET.
6  VCC  - Supplies the IC. This pin is connected to an external bulk capacitor of typically 10 F.
7 NC − This unconnected pin ensures adequate creepage distance.
8 HV -  High−voltage pin .Connected to the high−voltage rail, this pin injects a constant current into the VCC bulk capacitor and ensures a clean lossless startup sequence.

POWER SUPPLY CIRCUIT DIAGRAM 

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Category: LCD Monitor Repair and Service 

Contents of this article

LENOVO L2021 

Maintenance

Maintainability Requirement
1. Voltmeter. & digital multimeter
2. Oscilloscope.
3. Pattern Generator.
4. DDC Tool with Compatible Computer.
5. Alignment Tool.
6. LCD Color Analyzer.
7. Service Manual.
8. User Manual.
9. repair tools etc

Disassembly SOP
Precaution
Please read the precautions as follows to prevent any damages to the LCD Monitor
Make sure all power connection is removed. Be sure that the LCD Monitor is in power off status.

1.Prepare soft cloth and sponge as working platform to place LCD monitor horizontally.

2. Hold LCD by the side carefully and DON’T touch or press panel directly.

3. appropriate tools
select the appropriate tools for disassembly and re-assembly.

Phillips screwdriver
spacer screwdriver
C/D Disassembly Tool
Gloves or soft cloth

Software update step
After replacing the Main board and the Panel, Check if white-balance is within the specs ,then re-writing DDC is necessary.
Software information

U401	056G1125191	IC RTD2122L-LF LQFP-48
SMTCR-U401	100GLRSA006B11	L2021W_SEC_LTM200KT03_M20_ RTD2545LH_100729_v0.01_Eng.H00
U501	056G 562201	IC RTD2545LH-GR QFN-48
	CBPCARJG1J1	G3327-1-X-X-2-090407 FOR L2021WA

1. Connect USB cable to the PC USB port and the ISP tool,（ 715GT089-B）；
2. Will be the Monitor VGA cable to connect ISP tool ；
3. ISP tool card connection as shown below

Step2： Installing driver software
1.To install the USB driver software, mstar ISP Driver3-DB07-6-XP-driver

Step3： Run software “RTD Tool V1.7 version”

1.selected ISP,-àRTD2122 ,as shown in, Press the icon to select,Note save HDCP key:

2.selcted “Page Select”

3.Click “64K”,selcted software files

In this way, Automatic Identification space size,Next ,selected “Externd True Size”

4.Click Program icon ,Programming started,After Programming, Appear PASS.

Writing DDC program step
1. Prepared the PC with Windows XP system, DDC recording device (12V)for figure below
2. Connect the DDC recording device and the PC through PC parallel port
3. setup “Port95nt” driver program to PC ,
4. select relevant program and run it, below figure will appear
5, Press “LoadFile”, select EDID -model of product, and select input port;
6. key in SN,and other informatiom, key-press “Pragram” button;

SERVICE MODE

Factory mode adjustment
After replacing the Main board and the Panel, Check for enter the Factory mode ,then re-writing DDC is necessary.
Press MENU button and hold,reinsert the Power cord , then ,press MENU , the monitor will may enter Factory OSD Menu. Then Press . Factory OSD Menu will appear in the screen.

In normal user mode, open the menu to restore factory default values

 POWER SUPPLY CIRCUIT DIGRAM 

Power Board715G4174-2

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