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[OswaltHut]

HL67A750 LED set just died without notice... Tries to power on 3 times in a row with musical chimes (no picture or sound), then just gives me the 3 flashing lights up front & nothing! Set is just over 2 yrs old and has always worked fine - now nothing. Removed back and observed all 3 fans running ok, both ceramic fuses checked good, saw no obvious damage (including known issue with blown capacitors), went ahead and replaced whole sub-unit power supply near LED light engine with no change... Bought this unit because I figured the LED light engine would be more reliable than replacing projector lamps every few years, but I'm really stumped! Any ideas would be appreciated. Thanks.

[grayfox]

Hello,
wow, so you got no distortion before the TV went straight to the 3 blinking dots? and you replaced the LCD optical block?
If so this can be a simple issue with the Colorwheel or Ballast, depending on the reasons this is not booting up (any grinding bearing sounds would be the colorwheel, and any clicking buzzing sounds would be the ballast...) other than that, have you ever replaced the lamp?

[OswaltHut]

Nope, no picture distortion or anything - just turned it on after work and no workie. Not sure what part you're referring to when you say LCD optical block, I'm just replaced the kinda triangular shaped submodule power supply mounted vertically at the very back right side because it sounded like a common failure item (now thinking maybe it's the main power supply at the back left side)... Not sure what part you're calling the LCD optical block (don't think I've played with that at all) and the bulb's never been replaced because the Series 7 TVs don't use a bulb (they say it's LED-powered and those aren't prone to burning out). Any other ideas??

[grayfox]

true it is sorry i did not read the topic
this sound distortions can be coming from the input board or the DMD board... let me do some research!

[OswaltHut]

Yeah, have Samsung service manual and was gonna try and troubleshoot voltage output from DMD board, but the multi-pin connector is so small I'm not sure how to go about it using my regular multimeter...

[grayfox]

True the pins are tiny, but to be honest unless you know the amp/volt/watt you are looking for, it can be a waste of time since it can either send the wrong amount or not send any at all....

[OswaltHut]

Latest update - had Samsung tech look at it and confirmed main board and both power supply boards are good. Definitely a problem with the light engine. Any advice on most likely failures? Plan to try DMD board, then LED Driver Board... Anybody been down this road before??

[grayfox]

I am sure anybody with a light engine / DMD board issue has been down this road...

Good news is that you can buy the complete DMD/lightengine since they are usually sold together. And you will know almost all boards in your TV are working fine!

[OswaltHut]

Well, even if the entire LED Series 7 light engine is avail, I understand the cost would be almost $1000, which even the Samsung tech said makes no sense (better to invest the money in a brand new LCD or plasma tv). Just gonna have to take some time and figure out which component has failed so I can get this baby running again... In the meantime, this issue doesn't give me confidence in Samsung reliability, so went ahead and replaced it with a brand new Sharp 60" Quattron LED LCD set for $1500 - awesome picture & newer technology!

[grayfox]

yes NEVER go for plasma, but as far as Samsung DLP or any projection technology goes, they all have their flaws, some work for 8 yrs without as much as a lamp change, some need a lamp at the first year...
enjoy your new set!

[OswaltHut]

Just a quick update for anyone having video problems with the Samsung Series 7 LED big screens - FINALLY found the source of my problem and FIXED this beautiful TV! Frankly, was just about ready to junk it after replacing the sub-power asy (typically a high fault rate component due to bad capacitors) and also the main DMD board (recommended by Samsung tech, although he didn't do much troubleshooting). Had pretty much given up hope but decided to give it one last chance... Turns out I was able to pull the entire light engine out without much difficulty, confirm the 3 LEDs (red, blue, & green) were all good by simply touching a 9-volt batt to the top of each one, which then pretty much narrowed the problem down to the actual LED driver board itself. Ordered a used board thru eBay ($67) and EUREKA! Problem solved! This TV has one of the best pictures I've ever seen and it's wonderful to have it working again!

[AlanfUp]

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