When the lamp on your DLP blows out or the "replace lamp" light says it's time to replace the lamp, you do, then the unit will not power on you may not have inserted the lamp fully, correctly or the interlock switch may not be closing completely on the lamp door.
For safety purposes DLP TV's have an electrical interlock where the lamp door closes. The set cannot be energized with the lamp door off or open. If you remove the lamp door you should see an arm on the door and a slot in the frame with the contact for the switch visible through it. Make sure that the arm is not broken off or damaged in any way.
With the door removed, remove the lamp assembly being careful not to touch any of the glass. If you still have the replacement instructions reread them and follow the reassembly instructions carefully.
Be certain that the lamp assembly is installed properly and seated completely on the power plug. When you are absolutely sure that it is mounted correctly, attach the lamp door making certain that the interlock is being depressed by the arm on the door.
If the unit still does not power on remove the back from the set. This generally involves removing many screws around the perimeter and should be obvious if studied for any length of time. Once the back is removed look at the interlock switch and make sure it is mounted correctly. Many times removing and reinstalling the lamp door will move the switch (if it is loose) causing the switch to not perform it's task and clear the fault for the lamp door.
If the unit appears to be mounted correctly use a DMM to check the continuity of the switch both open and closed. If the switch shows continuity when depressed it is good. Reassemble the unit and try it. If the lamp door switch was the problem you unit should now work.
If your unit still will not work I have a tip at http://www.fixya.com/support/r4606286-troubleshoot_dlp_tv
which may be helpful for more advanced troubleshooting.
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