Saturday, January 02, 2016

LG 32CL10 Service adjustments - LCD Television Repair

Category: LCD Television Repair  

Contents of this article 

  • Service Adjustments
  • White balance Adjustment 
  • Replacing parts  



LG 32CL10 

Application range
This specification is applied to the LCD TV used LA92A chassis.
Requirement for Test
Each part is tested as below without special appointment.
1) Temperature : 25±5ºC (77±9ºF), CST : 40±5ºC
2) Relative Humidity : 65±10%
3) Power Voltage : Standard input voltage(100~240V@50/60Hz)
* Standard Voltage of each products is marked by models.
4) Specification and performance of each parts are followed each drawing and specification by part number in accordance with BOM.
5) The receiver must be operated for about 5 minutes prior to the adjustment.
Max Luminance &Contrast measure standard specification
- Max Luminance measure specification
1) In non-impressed condition, measure peak brightness displayable as much as possible LCD module.
2) Measuring instrument: CA-210 or a sort of Color Analyzer.
3) Pattern Generator :VG- 828 or a sort of digital pattern generator (displayable Full White &1/25 White Window pattern)
4) Measure condition
# Test pattern: in center,1/5(H)*1/5(V) of Window Pattern (white pattern in non-impressed condition)
# SET condition: Contrast &Brightness Level 100%
# Environment condition : Dark room in the non outside light
# Video menu option condition
5) Measurement
# Do heat-run LCD module at 30minutes in normal temperature (25°C)by using full white pattern of 15%signal level(38 gray level).
# Impress test pattern signal in 1/5(H)*1/5(V)White Window of 100%(255Gray Level)
# measure 3 times brightness of central white window,and mark peak brightness in max brightness degree
# measure the same condition in video signal /RGB signal.
- Luminance uniformity measure specification
1) Impress 100%(255Gray Level) full white pattern at the same peak brightness measurement.
2) Measure average brightness in 5 points.
Contrast ratio measure specification
1) Test display signal :30*30 dots White Window signal &all Black Raster signal
2) Dark room measure condition: Using touch type Color analyzer CA-210 Dark room in the non outside light
3) Bright room measure condition: In bright room of 150Lx illumination in the panel surface, locate a source of light on the above
45º of the panel surface.
4) Measure method
3 In standard test condition,impress 30*30 dots White Window Pattern signal .
Measure center peak brightness degree Lw of white window
# Impress black Raster signal as contrast ratio measurement signal.
Measure black brightness degree Lb of PDP central
Calculate the following numerical formula.
Contrast ratio =Lw /Lb
If it does not use Prior measurement, use generally simple test measurement. The Correct measure specification is followed
by IEC61988-2/CD,JAPAN EIAJ-2710
ADJUSTMENT
Notes
(1) Because this is not a hot chassis, it is not necessary to use an isolation transformer. However, the use of isolation transformer will help protect test equipment.
(2) Adjustments must be done in the correct order.
(3) The adjustments must be performed in the circumstance of 20±5°C of temperature and 65±10% of relative humidity if there is no specific designation.
(4) The input voltage of the receiver be must kept 100V-240V, 50/60Hz when adjusting.
(5) The receiver must be operated for about 5 minutes prior to the adjustment when module is in the circumstance of over 15.
In case of keeping module is in the circumstance of 0°C, it should be placed in the circumstance of above 15°C for 2 hours
In case of keeping module is in the circumstance of below - 20°C, it should be placed in the circumstance of above 15°C for 3 hours,.
Caution : When still image is displayed for a period of 20 minutes or longer (especially where W/B scale is strong. Digital pattern 13ch and/or Cross hatch pattern 09ch), there can some afterimage in the black level area.
Main PCB check process
- Adjust 480i Comp1
- Adjust 1024*768 RGB
Above adjustment items can be also performed in Final Assembly if needed. Both Board-level and Final assembly adjustment items can be check using In-Star Menu 1.ADJUST CHECK.
ADC Adjustment
(1) Overview
ADC adjustment is needed to find the optimum black level and gain in Analog-to-Digital device and to compensate RGB deviation.
(2) Equipment & Condition
1) Jig (RS-232C protocol)
2) MSPG-925 Series Pattern Generator(MSPG-925FA)
- Resolution : 480i Comp1 (MSPG-925FA: model-209, pattern-65)
1024*768 RGB (MSPG-925FA: model-60 , pattern-65)
- Pattern : Horizontal 100% Color Bar Pattern
- Pattern level : 0.7±0.1 Vp-p
- Image
ADC(Saturn5) Adjustment
(1) Overview
ADC adjustment is needed to find the optimum black level and gain in Analog-to-Digital device and to compensate RGB deviation.
(2) Equipment & Condition
1) Adjust Remocon
2) 801GF(802B, 802F, 802R) or MSPG925FA Pattern Generator
- Resolution: 480i, 1024*768
- Pattern : Horizontal 100% Color Bar Pattern
- Pattern level: 0.7±0.1 Vp-p
- Image
Adjust method
# ADC 480i Comp1
1) Check connected condition of Comp1 cable to the equipment
2) Give a 480i Mode, Horizontal 100% Color Bar Pattern to Comp1.
(MSPG-925FA Ë Model: 209, Pattern: 65)
3) Change input mode as Component1 and picture mode as “Standard”
4) Press the In-start Key on the ADJ remote after at least 1 min of signal reception. Then, select 7. External ADC -> 1. COMP 480i on the menu. Press enter key. The adjustment will start automatically.
5) If ADC calibration is successful, “ADC RGB Success” is displayed. If ADC calibration is failure, “ADC RGB Fail” is displayed.
6) If ADC calibration is failure, after recheck ADC pattern or condition retry calibration. Error message refer to (v)
# ADC 1024*768 RGB
1) Check connected condition of Component & RGB cable to the equipment
2) Give a 1024*768 Mode, 100% Horizontal Color Bar Pattern to RGB port. (MSPG-925 Series Ë model:60 , pattern:65 )
3) Change input mode as RGB and picture mode as “Standard”
4) Press the In-start Key on the ADJ remote after at least
1 min of signal reception. Then, select 7. External ADC -> 1. COMP 480i on the menu. Press enter key. The adjustment will start automatically.
5) If ADC calibration is successful, “ADC RGB Success” is displayed. If ADC calibration is failure, “ADC RGB Fail” is displayed.
6) If ADC calibration is failure, after recheck ADC pattern or condition retry calibration
EDID(The Extended Display Identification Data)/DDC(Display Data Channel) download
Reference : Download is only possible in POWER ONLY MODE
(1) Overview
It is a VESA regulation. A PC or a MNT will display an optimal resolution through information sharing without any necessity of user input. It is a realization of “Plug and Play”.
(2) Equipment
- Since embedded EDID data is used, EDID download JIG, HDMI cable and D-sub cable are not need.
- Adjust remocon
(3)Download method
1) Press Adj. key on the Adj. R/C,
2) Select EDID D/L menu.
3) By pressing Enter key, EDID download will begin
4) If Download is successful, OK is display, but If
Download is failure, NG is displayed.
5) If Download is failure, Re-try download.
Caution) When EDID download, must remove RGB/HDMI cable.
White Balance Adjustment
(1) Overview
# W/B adj. Objective & How-it-works
- Objective: To reduce each Panel’s W/B deviation
- How-it-works: When R/G/B gain in the OSD is at 192, it means the panel is at its Full Dynamic Range. In order to prevent saturation of Full Dynamic range and data, one of R/G/B is fixed at 192, and the other two is lowered to find the desired value.
- Adj. condition : normal temperature
1) Surrounding Temperature: 25±5ºC
2) Warm-up time: About 5 Min
3) Surrounding Humidity: 20% ~ 80%
(2) Equipment
1) Color Analyzer: CA-210 (NCG: CH 9 / WCG: CH12)
2) Adj. Computer(During auto adj., RS-232C protocol is needed)
3) Adjust Remocon
4) Video Signal Generator MSPG-925F 720p/216-Gray (Model:217, Pattern:78)
-> Only when internal pattern is not available
# Color Analyzer Matrix should be calibrated using CS-1000
Adj. method
# Auto adj. method
1) Set TV in adj. mode using POWER ON key
2) Zero calibrate probe then place it on the center of the Display
3) Connect Cable(RS-232C)
4) Select mode in adj. Program and begin adj.
5) When adj. is complete (OK Sing), check adj. status pre mode (Warm, Medium, Cool)
6) Remove probe and RS-232C cable to complete adj.
* W/B Adj. must begin as start command “wb 00 00”, and finish as end command “wb 00 ff”, and Adj. offset if need
# Manual adj. method
1) Set TV in Adj. mode using POWER ON
2) Zero Calibrate the probe of Color Analyzer, then place it on the center of LCD module within 10cm of the surface..
3) Press ADJ key -> EZ adjust using adj. R/C > 6. WhiteBalance then press the cursor to the right (KEY
G).
(When KEY(G) is pressed 216 Gray internal pattern will be displayed)
4) One of R Gain / G Gain / B Gain should be fixed at 192, and the rest will be lowered to meet the desired value.
5) Adj. is performed in COOL, MEDIUM, WARM 3 modes of color temperature.
- If internal pattern is not available, use RF input. In EZ
Adj. menu 6.White Balance, you can select one of 2 Test-pattern: ON, OFF. Default is inner(ON). By selecting OFF, you can adjust using RF signal in 216 Gray pattern.

Adj. condition and cautionary items
1) Lighting condition in surrounding area Surrounding lighting should be lower 10 lux. Try to isolate adj. area into dark surrounding.
2) Probe location
- LCD: Color Analyzer (CA-210) probe should be within 10cm and perpendicular of the module surface (80°~ 100°)
3) Aging time
- After Aging Start, Keep the Power ON status during 5 Minutes.
- In case of LCD, Back-light on should be checked using no signal or Full-white pattern.
(6) Reference (White Balance Adj. coordinate and color temperature)
# Luminance: 216 Gray
# Standard color coordinate and temperature using CS- 1000 (over 26 inch)
USB S/W Download (option)
(1) Put the USB Stick to the USB socket
(2) Automatically detecting update file in USB Stick
- If your downloaded program version in USB Stick is Low, it didn’t work.
But your downloaded version is High, USB data is automatically detecting
(3) Show the message “Copying files from memory”
(4) Updating is staring.
5) Updating Completed, The TV will restart automatically
(6) If your TV is turned on, check your updated version and
Tool option. (explain the Tool option, next stage)
* If downloading version is more high than your TV have, TV can lost all channel data. In this case, you have to channel recover. if all channel data is cleared, you didn’t have a DTV/ATV test on production line.
* After downloading, have to adjust TOOL OPTION again.
1) Push "IN-START" key in service remote controller.
2) Select "Tool Option 1" and Push “OK” button.
3) Punch in the number. (Each model has their number.)
IC Remove/Replacement
Some chassis circuit boards have slotted holes (oblong) through which the IC leads are inserted and then bent flat against the circuit foil. When holes are the slotted type, the following technique should be used to remove and replace the IC. When working with boards using the familiar round hole, use the standard technique as outlined in paragraphs 5 and 6 above.
Removal
1. Desolder and straighten each IC lead in one operation by gently prying up on the lead with the soldering iron tip as the solder melts.
2. Draw away the melted solder with an anti-static suction-type solder removal device (or with solder braid) before removing the IC.
Replacement
1. Carefully insert the replacement IC in the circuit board.
2. Carefully bend each IC lead against the circuit foil pad and solder it.
3. Clean the soldered areas with a small wire-bristle brush. (It is not necessary to reapply acrylic coating to the areas).
"Small-Signal" Discrete Transistor Removal/Replacement
1. Remove the defective transistor by clipping its leads as close as possible to the component body.
2. Bend into a "U" shape the end of each of three leads remaining on the circuit board.
3. Bend into a "U" shape the replacement transistor leads.
4. Connect the replacement transistor leads to the corresponding leads extending from the circuit board and crimp the "U" with long nose pliers to insure metal to metal contact then solder each connection.
Power Output, Transistor Device Removal/Replacement
1. Heat and remove all solder from around the transistor leads.
2. Remove the heat sink mounting screw (if so equipped).
3. Carefully remove the transistor from the heat sink of the circuit board.
4. Insert new transistor in the circuit board.
5. Solder each transistor lead, and clip off excess lead.
6. Replace heat sink.
Diode Removal/Replacement
1. Remove defective diode by clipping its leads as close as possible to diode body.
2. Bend the two remaining leads perpendicular y to the circuit board.
3. Observing diode polarity, wrap each lead of the new diode around the corresponding lead on the circuit board.
4. Securely crimp each connection and solder it.
5. Inspect (on the circuit board copper side) the solder joints of the two "original" leads. If they are not shiny, reheat them and if necessary, apply additional solder.
Fuse and Conventional Resistor Removal/Replacement
1. Clip each fuse or resistor lead at top of the circuit board hollow stake.
2. Securely crimp the leads of replacement component around notch at stake top.
3. Solder the connections.
CAUTION: Maintain original spacing between the replaced component and adjacent components and the circuit board to prevent excessive component temperatures.
Circuit Board Foil Repair
Excessive heat applied to the copper foil of any printed circuit board will weaken the adhesive that bonds the foil to the circuit board causing the foil to separate from or "lift-off" the board. The following guidelines and procedures should be followed whenever this condition is encountered.
At IC Connections
To repair a defective copper pattern at IC connections use the following procedure to install a jumper wire on the copper pattern side of the circuit board. (Use this technique only on IC connections).
1. Carefully remove the damaged copper pattern with a sharp knife. (Remove only as much copper as absolutely necessary).
2. carefully scratch away the solder resist and acrylic coating (if used) from the end of the remaining copper pattern.
3. Bend a small "U" in one end of a small gauge jumper wire and carefully crimp it around the IC pin. Solder the IC connection.
4. Route the jumper wire along the path of the out-away copper pattern and let it overlap the previously scraped end of the good copper pattern. Solder the overlapped area and clip off any excess jumper wire.
At Other Connections
Use the following technique to repair the defective copper pattern at connections other than IC Pins. This technique involves the installation of a jumper wire on the component side of the circuit board.
1. Remove the defective copper pattern with a sharp knife. Remove at least 1/4 inch of copper, to ensure that a hazardous condition will not exist if the jumper wire opens.
2. Trace along the copper pattern from both sides of the pattern break and locate the nearest component that is directly connected to the affected copper pattern.
3. Connect insulated 20-gauge jumper wire from the lead of the nearest component on one side of the pattern break to the lead of the nearest component on the other side. Carefully crimp and solder the connections.
CAUTION: Be sure the insulated jumper wire is dressed so the it does not touch components or sharp edges.