Sunday, July 26, 2015

HOW TO TROUBLESHOOT RCA DLP PROJECTION TVs

DLP PROJECTION TV Troubleshooting Hints _ Service Menu _ Voltage chart to connectors
Important: Before replacing any circuit boards, recover the “Last Failure” code using Chipper Check. Also, it’s very important when troubleshooting to accurately identify the symptom in order to quickly isolate which circuit board or item has failed. The
‘Probable Causes’ listed in the accompanying procedures are in there ‘most likely order’, 1, 2, 3, etc.
Symptom: Dead Set/No Start (No relay click/No Power LED when AC applied)
Probable Cause:
1. Main Power Supply Board
Standby voltage is needed by the DM2CR and is obtained from the AC IN CBA. If the standby supply doesn’t turn on when AC is applied, the relay will not energize and the DM2CR doesn’t have the supply it needs.
2. DM2CR Module
If the power supply is OK but the DM2CR doesn’t respond to power on commands then the DM2CR module has likely failed.
Symptom: No Picture, Audio OK
(Relay click OK when AC applied, Power LED Flashes 4-5 times then stays on)
NOTE: The LED will only flash one time (4 to 5 flashes) and the unit must be reset by unplugging AC to get unit to flash again.
Probable Cause:
1. Lamp assembly
Obtain failure code with Chipper Check before replacing (or subbing) lamp assembly. A flashing Power LED indicates a lamp or lamp power supply failure and the lamp assembly is the most likely cause.
2. Lamp power supply
If the Power LED still flashes after replacing the lamp assembly, replace lamp power supply
3. Main Power Supply Board
The source voltage for the lamp power supply is developed on ACIN CBA.
Symptom: Pixelization, Digital Freezing &/or Digital Noise/Artifacts
Probable Cause:
1. Weak terrestrial (ATSC) signal
A weak ATSC terrestrial (check strength of terrestrial signal) signal can cause pixelization or freezing. An external antenna can dramatically improve ATSC reception.
2. Formatter CBA
Apply 2H YPrPb to an external input. If pixelization is still present replace Formatter CBA.
3. DM2CR module
Always perform a ‘Reset’ by removing and reapplying AC Power. If pixelization not present with 2H YPrPb applied to external inputs, replace DM2CR.
4. Light Engine
Before replacing light engine, confirm picture quality issues by accessing the test patterns in the service menu 80. All patterns accept the cross hatch are generated by the formatter CBA. The cross hatch is generated by the light engine.
Symptom: Instrument starts normally then shuts down (runs 20-30secs)
NOTE: When unit shuts down, Power LED blinks three (3)
times. Set restarts automatically after 20-30 seconds. After 3rd cycle unit remains shutdown (unplugging resets unit).
Probable Cause:
1. Failure of lamp cooling fan or DLP device cooling fan.
Symptom: Poor Picture Quality (spots, discoloration, color impurities, etc.)
Probable Cause:
1. Poor Signal Quality
Whenever dealing with picture quality issues, always check quality of signal source before servicing unit.
2. Light Engine
Before replacing light engine, confirm picture quality issues by accessing the test patterns in the service menu 80. All patterns accept the checker board are generated by the ormatter CBA. The checker board is generated by the light engine.
Symptom: Rotated or Offset Picture
Probable Cause:
1. Mis-aligned Light Engine or centering.
Perform mechanical rotation adjustment of light engine and/or use service menu 76 to adjust horizontal and vertical centering.
Symptom: Stuck pixels
(Black and/or White)
Probable Cause:
1. Light Engine
The DLP defect tolerance specification allows for no more than 2 dark pixels and 0 bright pixels.
Symptom: Dead Set, No Power LED
(20-25sec boot when AC is applied, relay click OK when AC applied)
Probable Cause:
1.DM2CR module
When AC is first applied the DM2CR goes through a boot up sequence. If the Power LED doesn’t light when AC is applied, the DM2CR is not booting.
Symptom: Dead Set, Power LED stays ON when AC is applied (relay click OK when AC applied)
Probable Cause:
2.DM2CR module
When AC is first applied the DM2CR goes through a boot up sequence. If the Power LED remains on when AC is applied (should go off in 20-25sec), the DM2CR is not booting properly.
Service Menus & Diagnostics
Service Menu (V:76): Turn instrument on, then press and hold Channel Down & Menu simultaneously. Next, select Service Alignment in menu, then volume Up to V:76 then Channel Up and Down to desired adjustment. After selecting adjustment, Volume Up/Down changes value of adjustment. Press off to exit.
Test Patterns (V:80): Enter service menu and volume up to V:80. Channel up to go to patterns. The skip button toggles the pattern and the menu button toggles between the pattern and normal video. To exit, press the off button.
Usage Clock (V:90): Enter service menu and volume up to V:90. Channel up for usage clock. Press off to exit.
Error Codes (V:50): Enter service menu and volume upto V:50. Channel up for first failure code. Channel up for next of 8 failure codes. Pressing clear removes error code. Last error is most recent failure code. I.E: if four (4) errors are listed, four is the most recent. To exit, press the off button.
DM1 Warm Reset: Press and hold Channel Down & Power button simultaneously for approximately 3 secs.
Voltage Chart
Note: All voltages measured with a Fluke VOM ON 200V range. Standby voltages measured after run supply has been off for greater than 2 minutes. Ground for all ACIN voltages connected to JW24630, grid coordinate II02.
Service Menus & Diagnostics
Service Menu (V:76): Turn instrument on, then press and hold Channel Down & Menu simultaneously. Next, select Service Alignment in menu, then volume Up to V:76 then Channel Up and Down to desired adjustment. After selecting adjustment, Volume Up/Down changes value of adjustment. Press off to exit.
Test Patterns (V:80): Enter service menu and volume up to V:80. Channel up to go to patterns. The skip button toggles the pattern and the menu button toggles between the pattern and normal video. To exit, press the off button.
Usage Clock (V:90): Enter service menu and volume up to V:90. Channel up for usage clock. Press off to exit.
Error Codes (V:50): Enter service menu and volume upto V:50. Channel up for first failure code. Channel up for next of 8 failure codes. Pressing clear removes error code. Last error is most recent failure code. I.E: if four (4) errors are listed, four is the most recent. To exit, press the off button.
DM1 Warm Reset: Press and hold Channel Down & Power button simultaneously for approximately 3 secs.
Voltage Chart
Note: All voltages measured with a Fluke VOM ON 200V range. Standby voltages measured after run supply has been off for greater than 2 minutes. Ground for all ACIN voltages connected to JW24630, grid coordinate II02.