Saturday, December 12, 2015

SAMSUNG CL15A8L7X/STR - CL21A8W7X/RCL - CL25A6W7X/RCL SERVICE MODE AND ADJUSTMENTS

Contents of this article 

  • How to enter to Service mode 
  • White balance adjustment
  • High voltage check  

SAMSUNG CL15A8L7X/STR - CL21A8W7X/RCL - CL25A6W7X/RCL

Factory Adjustment
To enter the “Service Mode”, Press the remote-control keys in this sequence :
- If you do not have Factory remote-control
PICTURE OFF > PICTURE ON > MUTE > 1 > 8 > 2
If you have Factory remote-control
PICTURE ON > DISPLAY > FACTORY
Use the Channel Up/Down buttons to move the cursor in the adjustment parameters.
Note :
- When CRT, CRT PCB, FBT, E2PROM (sometimes MICOM) is replaced, the adjustment values should be controlled.
- After the Service adjustment is completed, Do not select “Reset” in the service mode menu. (After above procedure is done, power is on initially and the “Plug and Play” will be operated.)
White Balance Adjustment
Equipment : Color-Analyzer (CA-100)
Input Signal : Pattern signal (Toshiba pattern)
1. Select STANDARD from the menu.
2. Input an 100% White pattern.
3. Enter the “Service Mode”.
4. Warm up the TV set at least for 30 minutes.
5. Input a Toshiba pattern signal.
6. Enter the “Video Adjust1”.
Adjust “Sub Contrast” so that Y (luminance) becomes 65 ft ± 3.
Use “Red Drive” and “ Blue Drive” to adjust High-Light (x : 265, y : 265)
Adjust “Sub Bright” so that Y (luminance) becomes 1.2ft ± 0.3.
Use “Red Cutoff” and “Blue Cutoff” to adjust Low-Light (x : 265, y : 265).
7. Adjust CA-100 so that the final adjustment value can be fixed.
8. Use the Channel Up/Down (
UP / DOWN) buttons to move the cursor on the adjustment modes.
9. Use the Volume +/- buttons to change the adjustment value.
E2PROM (IC902) Replacement
1. When IC902 is replaced, all adjustment data revert to the initial values. So, all adjustment values when servicing should be readjusted.
2. After IC902 is replaced, connect the AC power supply cord.
3. Turn the power switch ON.
4. In stand-by, warm up the TV for at least 10 seconds.
5. Power on the TV.
SCREEN Adjustment
1. Input Toshiba Pattern
2. Enter “Service Mode”.
3. Select “G2-Adjust”.
4. Set the values
5. Turn the SCREEN VR until “MRCR G B” and “MRWDG” are green and those value are about 100. (The incorrect SCREEN Voltage may result that “MRCR G B” and “MRWDG” should be red)
High Voltage Check
CAUTION : There is no high voltage adjustment on this chassis. The B+ power supply should be +135 volts (with full color- bar input and normal picture level).
1. Connect a digital voltmeter to the second anode of the picture tube.
2. Turn on the TV. Set the Brightness and Contrast controls to minimum (zero beam current).
3. Adjust the Brightness and contrast controls to both extremes. Ensure that the high voltage does not exceed 30 KV under any conditions.
Degaussing
A degaussing coil is mounted around the picture tube, so that external degaussing after moving the TV should be unnecessary. But the receiver must be properly degaussed upon installation.
The degaussing coil operates for about 1 second after the power is switched ON. If the set is moved or turned in a different direction, the power should be OFF for at least 10 minutes.
If the chassis or parts of the cabinet become magnetized, poor color purity will result. If this happens, use an external degaussing coil. Slowly move the degaussing coil around the faceplate of the picture tube and the sides and front of the receiver. Slowly withdraw the coil to a distance of about 6 feet before turning power OFF.