My HLN467W/HLN567W TV won't turn on. One moment it was working, and the next it died and it won't turn on again.

check fuel pressure could have clogged fuel filter or bad fuel pump.

could have worn timing chain engine slipped time or could have faulty ignition module or CKP sensor.

Check all fuses ,wiring anywhere short or check alternatour

Well, I would try to check the spark to make sure the ignition system is providing spark to the spark plugs. Then, I would check fuel pressure, to make sure that the injectors are getting enough pressure to provide gas to the cylinders, using a fuel pressure gauge on the rail.

Most likely your problem is on the DMD Assy Board P/N BP96-00249A . More presicely there is a few bad electronic components on that board that are bad. That board can be repaired by replacing the bad components (and the other few compoonents that are probly going bad and will soon cause your tv to lockup and lose remote and button functions when it fails so you will need to unplug it to get it on again).
Or the DMD board can be replaced .But it is not a cheap board.
For removal and Installation of the DMD board I would reccomend a tv service person because it is in the heart of the television and there are some adjustements to be made when the new board is installed.
To get the new board you could probably find it by just gooogling the part number.
Component level repair would require some experience in desoldering and soldering SMT,SMD , and or surface mount components.The actual components are about $15.00 total so just repairing your board should cost about $125.00 by a qualified servicer (if you were to remove and install it yourself). This DMD board is used in many models and can a few common problems.
HLM437W HLM4365W HLM5065W HLM507W HLM617W HLN437W HLN4365W HLN467W HLN507W HLN50665W HLN567W HLN617W ( L2 and L5 chassis )
SYMPTOMS:
-Intermittant picture freezing with a negative looking B/W frozen picture.
-Intermittant loss of pic with/without shutdown,abnormal color wheel noise if attempted to start after shutdown.
-lockup of tv control functions . Remote and front keypad do nothing , TV must be unplugged to reset .
-horizantal tearing, distortion , flippnig , solarization , red picture, leading to blank screen and lockup.(tv menu would be affected by all picture defects).
Hope this helps someone..

if all three lights on the front blink when it stops then yes. you can removed the colorwheel and inspect it most of the time if the sound is loud the colorwheel is shattered

Replace your lamp

remove the lamp and visually check if inside looks broken.if visually do not see any thing wrong,check if you have 300 volts dc supply on the ballast which starts the lamp.if you do then the ballast may be defective.if you do not then the power supply should be checked.
the lamp should always be tried first especially if is older than two years.
note - be aware about the switch at the door lamp.the door should be closed,otherwise tv will not work.if you remove the back cover,make sure to bypass the switch temporarely so you could work on the set.

I would wait to see if it happens again.

It sounds like your rptv lamp is going out. If this is an older DLP this is most likely the cause. You can get a replacement at www.laptopsforless.com part number BP96-00224J for $151. If the tv is still under warranty, I would have them do it, otherwise replace it yourself. If so here is a link to give you step by step instruction. Please give me a good rating. ;-)