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Help please - Samsung HL67A750 DMD Chip - screen very blurry after replacement

post #1 of 9
6/19/12 at 10:17am
Thread Starter 
I have just replaced the DMD chip on my HL67A750A1FXZA and now after I have reassembled everything, the picture is blurry on screen. No amount of adjustment of the Focus Ring will make this issue go away, so I am assuming there is something amiss with the chip alignment?

I was very careful NOT to remove any screws other than the required ones (chips holding the metal frame, heat sink, board, and the spring-loaded ones) and didn’t touch the mirror assembly or anything behind the DMB board itself).

What could I have done wrong, or is there some adjustment I’m not aware of?

Any help would be appreciated! I searched for this issue and couldn't find a similar complaint.
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post #2 of 9
6/19/12 at 10:29am
Sent u a PM.
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post #3 of 9
6/19/12 at 10:57am
Thread Starter 
Thanks. Sent you a reply.
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post #4 of 9
6/19/12 at 3:01pm
For those who are following...

Here is a check list if you are going to be replacing a chip on your own.

1) Some chips have a protective coating over the glass... some coatings are blue or clear plastic. The clear plastic may seem transparent, but will cause a blurry picture if left covering the mirrors.

2) There is a guide that keeps the DMD board assembly (tray) in place. Check to see proper contact between DMD assembly and main chassis, so that there is no binding.

3) When assembling the lens to the DMD board, be sure to check carefully how it fits. Do a thorough check on mating before dis-assembly, it reduces time and effort in proper assembly.

4) Be very careful of the lens, any finger prints can cause major picture quality issues. Setting it in a new unused large zip-loc bag will keep contaminants from attaching to the lens while disassembled.

5) Take time in assembling everything... the smallest gap or skew may make a world of difference.
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post #5 of 9
6/19/12 at 3:17pm
Thread Starter 
Thanks to both of you for your help.

I'm probably going to try to disassemble everything again and go through the reassembly step by step, although I followed the service manual step by step in what I thought (!) was a slow and methodical way, and I can't see where I made an error. I was careful not to touch the chip surface, since I knew I'd be in big trouble if that happened.

I'm wondering if something is slightly askew or twisted after reassembly.

The service menu is no good to me since I have no way to read the writing on the screen due to the blurriness...it's literally impossible to make out any of the larger lettering, let alone the service menus frown.gif

Is there some manual physical adjustment that can be tweaked using the spring-loaded screws or some other mechanism?

Thanks.
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post #6 of 9
3/4/13 at 9:58am
I am having the same "white dot" issue. Where did you purchase the DMD chip? Is replacement of the chip a difficult proposition for a semi-techie?
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post #7 of 9
3/11/13 at 7:03pm
I am in the same boat with white dots on my HL67A750 TV. You can get a service manual here http://www.tradebit.com/filedetail.php/133052760-samsung-hl61a750a1f-hl67a750a1f-dlp-tv-service-manual
For $12.99.
You can buy the chip at Amazon here. http://www.amazon.com/Samsung-Mitsubishi-Toshiba-4719-001997-Chip/dp/B007JY58FM/ref=sr_1_fkmr0_1?s=electronics&ie=UTF8&qid=1363053477&sr=1-1-fkmr0&keywords=Dmd+chip+for+hl67a750. For $159.

I only have 4 dots now, but if it gets worse i will get the manual and the chip as I described above. Best of luck.
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post #8 of 9
3/11/13 at 7:40pm
My white dot suddenly disappeared. I have no idea why, but I'm hoping it is gone for good!
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post #9 of 9
3/11/13 at 9:21pm
Here is an instruction video from ShopJimmy. It may save the price of the Service Manual. They sell the DLP Chip on Amazon that I mentioned in my previous post.
http://m.youtube.com/watch?v=K7Jex2iJKvM
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