Thursday, January 21, 2016

DELL W2607C Service mode - White balance adjustment - Power supply Schematic circuit - FA5500 - STR-W6252 - LCD monitor repair and service - Tips manual

Category: LCD Monitor Repair and Service 

Contents of this article 

  • How to access service mode 
  • White balance adjustment 
  • Power supply circuit 


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 ├ćInitial 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 R
GB 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 R
GB 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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