Have an inherited 56HM195. One day upon power up it started a problem have not been able to find any information on. The screen will repeatedly, and at a regular pace, blink. Not on and off, but light and dark. This is accompanied by a clanking, or clunking, noise. Clank/darker, clank/lighter. And so on. The Guide comes up, the colors look normal, no out of place pixels, no off colors, no shadows. Just dim/bright dim/bright etc. Turn the set off, and the clanking continues for the entire length of the cooldown period, then finally ceases.
Looking thru the cracks and seams in the rear, it's pretty obvious that the lamp itself is not dimming, rather the light is reaching a certain point, the it is being mechanically manipulated light/dark. I can see a steady lamplight, then a short distance from the lamp assembly you can see the brightening/darkening.
Just on the off chance, I tried a different bulb, the cheapest I can find just for troubleshooting purposes (also have thought a $40 bulb would make a handy 'emergency' spare). No change. I didn't expect there to be. So I've ruled out the bulb, since I can see steady light leaking from the rear I'm inclined to rule out the ballast. The colors look okay so not the color wheel. Don't see dead or bright pixels so I'm not inclined to think it's the DMD. Unless the light tunnel has the capability to redirect the light at will, the uniformity of the screen would rule out that.
So what's up?
At this point, with LED/LCD flat screens nearly as large being in the $400 and just-under range, I'm not favorably disposed to start shotgunning the problem by throwing money at it. I'd like to know, if anyone has come across this, the likely culprit so I can then decide whether it's worth it. I don't mind throwing a $100 bulb at it every couple years but if the next bulb (I should be near the end of the current OEM bulb life) PLUS parts is going to be, say, 3/4 or more the price of a new set outright, I'll pass on the repair.
Much as I like the television, I don't see any sense in spending too much, so if anyone has any idea that would be appreciated.