Saturday, December 12, 2015

SAMSUNG CB5038V5X/XST - CB5073T0X/XEC - CB5073V5X/XST - CB5079T0X/XEC SERVICE MODE AND ADJUSTMENTS

Contents of this article 
  • How to enter to Service mode 
  • Test pattern 
  • purity adjustment 

SAMSUNG CB5038V5X/XST - CB5073T0X/XEC - CB5073V5X/XST - CB5079T0X/XEC 
Factory Mode
1. Do not attempt these adjustments in the Video Mode.
2. The Factory Mode adjustments are necessary when either the EEPROM (IC902) or the CRT is replaced.
3. Do not tamper with the “Adjustment” screen of the Factory Mode menu. This screen is intended only for factory use.
When EEPROM (IC902) Is Replaced
1. When IC902 is replaced all adjustment data revert to initial values. It is necessary to re-program this data.
2. After IC902 is replaced, warm up the TV for 10 seconds.
When CRT Is Replaced
1. Make the following adjustments AFTER setting up after setting up purity and convergence 
White Balance
Sub-Brightness
Vertical Center
Vertical Size
Horizontal Size
Fail Safe (This adjustment must be the last step).
2. If the EEPROM or CRT is replaced, set PVA to 45 (factory mode) and set SC as follows.
14, 16 inch : 0
20 inch : 10
21 inch : 12
Factory/Service Mode
Procedure for the “Adjustment” Mode
1. This mode uses the standard remote control. The Service Mode is activated by entering the following remote-control sequence :
(1) SLEEP >FACTORY.
(2) STAND-BY > DISPLAY > P.STD > MUTE > POWER ON.
2. The “SERVICE (FACTORY)” message will be displayed. The Service Mode has four components: Adjustment, Test Pattern, Option Bytes and Reset.
3. Access the Adjustment Mode by pressing the
“VOLUME” keys ( Up or Down). The adjustment parameters are listed in the accompanying table, and selected by pressing the CHANNEL keys (
UP ,DOWN).
4. Selection sequences for the all system: DOWN or UP key:
AGC>VCO>SBT>SCT>SCR>SC>RG>GG> BG>CDL>BLU>PSL>PVS>PVA>PHS>NSR> STT
5. The VOLUME keys increase or decrease the adjustment values (stored in the non-volatile memory) when Adjustment Mode is cancelled.
6. Cancel the Adjustment Mode by re-pressing the “FACTORY” or “Power OFF” keys.
Test Pattern (Aging Mode)
1. This mode can be used during servicing, or for confirming that the convergence and purity adjustments are correct.
2. Access the Test Pattern parameters by pressing a CHANNEL keys (
UP ,DOWN) while the Service Mode is on. The cursor will move to the test pattern. Press the VOLUME keys. On-screen display:
# WHITE - NON -TTX MICOM ONLY
# AGING -  TTX MICOM
3. AGING Mode (Reference Only)
This pattern is used for pre-heating the CRT during manufacturing
—it is accessed in the factory by twice pressing the “SLEEP >  FACTOR >FACTORY “ key, then white pattern will be displayed.
Even if the TV power is cut off, the Aging Mode is not cancelled, The aging mode is cancelled by repressing the “FACTORY” key or pressing the local “CH UP/DOWN” keys.
Automatic 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 has been moved or turned in a different direction, disconnect its AC power for at least 30 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 removing power.
High Voltage Check
CAUTION: There is no high voltage adjustment on this chassis. The B+ power supply must be set to +125 volts (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. The high voltage should not exceed 27.5KV.
4. Adjust the Brightness and contrast controls to both extremes. Ensure that the high voltage does not exceed 27.5KV under any conditions.
Purity Adjustment
1. Warm up the receiver for at least 20 minutes.
2. Plug in the CRT deflection yoke and tighten the clamp screw.
3. Plug the convergence yoke into the CRT and set.
4. Input a black and white signal.
5. Fully demagnetize the receiver by applying an external degaussing coil.
6. Turn the CONTRAST and BRIGHTNESS controls to maximum.
7. Loosen the clamp screw holding the yoke. Slide the yoke backward or forward to provide vertical green belt.
8. Tighten the convergence yoke.
9. Slowly move the deflection yoke forward, and adjust for the best overall green screen.
10. Temporarily tighten the deflection yoke.
11. Produce blue and red rasters by adjusting the low-light controls. Check for good purity in each field.
12. Tighten the deflection yoke.