Light engines for DLP units have gone through many design changes making them easier to troubleshoot. Once the tv is out of warranty, it typically isn’t cost effective to replace an entire light engine.
A common DLP symptom is no function and all three front panel LEDs blinking. This symptom can be caused by four different items:
1. No Color Wheel Startup – The color wheel must start before any other operation in the DLP can commence. Press the power on button and listen for the color wheel to start spinning. If the color wheel does not start spinning it is probably defective
2. Defective Lamp – Unfortunately there is no way to test the lamp so it must be tested by substituting a known good lamp. Defective lamps may not show any observable flaw, additionally there is no quick way to test a lamp with a multi-meter.
3. Defective Ballast – A properly operating ballast will emit a crackle sound at startup. The crackle sound is the spark gap firing. If the spark gap sound is not heard verify the ~300V supply voltage is present. Also verify Lamp enable signal is being sent from the DMD board. The Lamp enable signal is a 5V peak to peak square wave. If the Lamp Enable signal is missing the DMD board is suspected to be defective. If the Lamp enable and ballast supply voltage is present the ballast is suspected to be defective.
4. Defective DMD Board – Using a process of elimination, if items 1-3 are okay it has to be a defective DMD Board. Verifying the Lamp enable signal described in item 3 is another method of testing the DMD board.
Check our our TV Parts section to find the replacement parts you need and get your television back up and running.
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