Dark Screen Shadow Spots


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Resist58
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Dark Screen Shadow Spots

Postby Resist58 » Thu Aug 05, 2010 11:35 pm

I just replaced my shattered color wheel and used a compressed air can to blow out a lot of dust from inside my 2003 Samsung HLN617 DLP TV. After a bit of picture scrambling the video now is fine, except for some spots showing up when the picture is dark. They look like shadows of something on a lens somewhere in the light engine. There is more of them in the center of the picture than anywhere else on the screen. I am positive everything I cleaned had no dust left on them. Has anyone seen anything like this on their TV?

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Re: Dark Screen Shadow Spots

Postby darkart77 » Fri Aug 06, 2010 2:40 pm

I haven't heard of these particular symptoms before, can you post another comment and add the problem and symptoms from the beginning before replacing the colorwheel.

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Re: Dark Screen Shadow Spots

Postby Resist58 » Sat Aug 07, 2010 12:30 am

Prior to the color wheel shattering apart, the screen went blank and got the 3 flashing lights on the front panel. A zapping sound (or so I thought), could be heard behind the TV. My initial thought was that my 6 month old lamp had failed. But after pulling the lamp out, it looked fine. So after taking the TV apart, I realized what I thought was a zapping electrical sound was actually the color wheel grinding away as the glass panels were breaking apart and hitting the housing.

The shadow spots only appeared on the screen after I replaced the color wheel. Maybe there are glass particles inside the tube that is after the color wheel. This seems unlikely because I was pretty thorough in the cleaning process, using a can of compressed air.

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Re: Dark Screen Shadow Spots

Postby Talos04 » Sat Aug 07, 2010 10:38 pm

I just had my color wheel replace on my Samsung DLP HLR5678wx and I am getting the same issues (I think). On Dark movies or shows, you can actually see a set of concentric rings, each a lighter shade then the preceding one on the dark places on the screen. On the faces of the actors, you can see red pixels within their faces. Also on their shirts and any other light object. It can be seen at night when the room is dark. The affect resembles a low quality image. Note that this is all in HD. I see no setting on the remote that effect this issue.

Is there some type of reset on the color wheel, or an adjustment that I can use to "fix" this issue?

The repair person from Accelerated TV repair based out of Portland Or. refused to honor their warranty and even come out and look at it. DO NOT USE THEM FOR YOUR TV REPAIR.

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Re: Dark Screen Shadow Spots

Postby Talos04 » Sun Aug 08, 2010 2:35 am

This is my second post on this subject. Here is what I did to "fix" the problem.

1.Turn off the tv to standby mode. 2.Press "mute"-1-8-2-"power" buttons on the remote. 3. From the Factory Service Mode Menu choose OPTION. 4. Select DMD-DIGITAL, press enter or right arrow key. 5. Press enter or right arrow key, OK should come up. 6. exit Factory Mode. Check the picture quality.

Index Delay adjustment: 1. Turn off the tv and press the same keys to get into the service menu as above. 2. Select "Service" on the first display of the service mode menu. 3. Press the arrow up or arrow down button to move to Index Delay, press enter. 4. The Index Delay screen will show. It has a red bar on the bottom. 5. Press the left or right arrow buttons to adjust to the mean value. (I've never done this and am not sure what the mean value is, so try to find the best shade of red???) Exit out of service menu.

I adjusted the setting to 35 and it fixed the issue for me. good luck.

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Re: Dark Screen Shadow Spots

Postby Resist58 » Mon Aug 09, 2010 10:36 pm

Talos04,

I don't think we have the same issue. I have shadow spots, not rings or red pixels. I think my issue is dust on a lens or the DMD mirrors, that is reflecting shadows to the screen. But as I had stated, you can only see them when the screen goes dark. I will try to post a picture of them.

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Re: Dark Screen Shadow Spots

Postby Resist58 » Wed Aug 11, 2010 8:09 am

Here is a picture of my issue.


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Re: Dark Screen Shadow Spots

Postby Resist58 » Thu Aug 19, 2010 2:18 am

Anyone know what these spots are from?

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Re: Dark Screen Shadow Spots

Postby darkart77 » Thu Aug 19, 2010 2:22 pm

the dark spots are normally cause by what you'd call dead pixels, this happens when the DMD board has a faulty chip.

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Re: Dark Screen Shadow Spots

Postby Resist58 » Fri Aug 20, 2010 10:28 am

They are not dark spots, they are gray. But if they are caused by "dead pixels" then why does it not effect the picture, other than when the screen is dark?

Are you sure it couldn't be shadows from debri, due to the previous shattered color wheel? I thought I got all the glass but might have missed some.

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Re: Dark Screen Shadow Spots

Postby darkart77 » Fri Aug 20, 2010 2:06 pm

well... the dead pixels I was telling you about "micro mirrors" they rotate depending on the picture, reflecting light or moving the opposite way to create a certain projection of the light. So if they stopped moving when you had a light image, once dark images come on they aren't able to move along with the rest of the microchips to create an even dark picture.

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Re: Dark Screen Shadow Spots

Postby Resist58 » Sat Aug 21, 2010 4:23 am

I understand how the micro mirrors work. But I would think if they were not working then it would effect the picture when content is shown. And as I said, the picture is fine, even perfect. The issue only shows up during a dark screen, as if debris is reflecting light. I never had this issue prior to replacing the color wheel.

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Re: Dark Screen Shadow Spots

Postby darkart77 » Mon Aug 23, 2010 2:42 pm

It is my understanding through """experience""" on these tv's. however It looks like you may know more than I.,
Best of luck.
p.s
Really?
guessing vs experience. you probably right :geek:

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Re: Dark Screen Shadow Spots

Postby Resist58 » Mon Aug 23, 2010 10:15 pm

Not sure what you are saying "really?" about. I have already explained to you that I am not getting dark spots or spots that are pixel size. These are larger light shadow spots or circles.

But, if you take a good look at the picture I posted you can see the majority of the circles are in the center of the screen with some fanning out on the sides. This seems very consistent with a spatter pattern due to glass debris. It appears to me failed mirrors would be in a more random pattern, certainly effecting the picture quality (which it does not). And as I stated earlier, this issue was not there prior to the color wheel shattering apart.

It would be very helpful if I can find someone else who's Samsung DLP TV showed the same effect on their TV as what is shown on my picture. I can't get any help from Samsung, they only say they no longer support this model of TV. All I want is them to confirm what the problem could be so I can fix it.

But I guess I just have to live with this issue, thank goodness it doesn't effect the picture quality when content is shown, only a dark blank screen.

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Re: Dark Screen Shadow Spots

Postby darkart77 » Tue Aug 24, 2010 2:51 pm

I understand the "larger light shadow spots or circles" and the explanation I gave you is relevant due to the fact that, it is produced by the same micro-mirrors. Get a Tech, to take a look if you want to get a more educated opinion from some one who's physically able to see the tv, After that you can get the board and replace it yourself PLUG AND PLAY PRETTY MUCH. Save some money by installing in yourself.
Keep me posted.

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Re: Dark Screen Shadow Spots

Postby Resist58 » Wed Aug 25, 2010 2:07 am

I agree replacing the board myself is easy to do, just time consuming. The only problem is I can't find the part anywhere. I have checked Discount Merchants and they don't have it for my TV, HLN617 model. I'm sure if they did it would be very expensive and for a used part that is just crazy.

It's strange though that this problem only popped up after replacing the shattered color wheel with a new one. This is why I believe what I am seeing are specks of dust on a lens somewhere within the light engine (maybe the light tube behind the color wheel), from when I used a can of compressed air to clean it up.

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Re: Dark Screen Shadow Spots

Postby darkart77 » Wed Aug 25, 2010 2:33 pm

Definitely give that a shot, take the tv out to an open area dust it out and if you're cleaning any glass, lenses. Make sure to use a semi-dry cloth, preferably the kind that don't leave any specs.
won't hurt to try it.

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Re: Dark Screen Shadow Spots

Postby Resist58 » Wed Aug 25, 2010 9:36 pm

Give what a shot? Replace the DMD board? As I stated, I can't find one anywhere.

If you meant to dust the TV out, as I stated I already did that when I replaced the color wheel. I thought I had all the glass cleaned really well, but may not have gotten all the broken color wheel particles. Not really in to big of a hurry though to pull the guts of the TV out all over again, as it's such a time consuming process. But if the issue is in fact glass particles from the old color wheel in the light tube, then I need to find out how to properly remove it. I can't find any instructions on how to do this without breaking something.

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Re: Dark Screen Shadow Spots

Postby johnrot » Fri Aug 27, 2010 7:26 pm

That can only be fixed by replacing the DMD board, if youre lucky you can find one available otherwise you will need to get the whole light engine ( which has the DMD board and the colorwheel already assembled ) i found some of them as i assume that this is the correct tv model number.

http://www.discount-merchant.com/Search ... =25&page=9

Hope this info. can help you :ugeek:
[b][color=#BF00FF]WE ALWAYS LEARN SOMETHING NEW[/color][/b]

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Re: Dark Screen Shadow Spots

Postby Resist58 » Sat Aug 28, 2010 1:17 am

Yes but which light engine is the correct part number for my HLN617 TV? There appears to be several different part numbers for my TV. Not so sure spending this much money is worth doing on a 7 year old TV. I have already spent $80 for the replacement color wheel and $110 on a new lamp earlier this year. It may be time to upgrade to a newer HD TV that has more inputs, including HDMI. I'd miss the 61" screen size though, seems like 55" has taken over.

I noticed something strange happening with the dark screen shadow spots now, they appear to be spreading out some. Either that or my eyes are playing tricks on me.

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Re: Dark Screen Shadow Spots

Postby Bubby » Sun Sep 26, 2010 3:16 pm


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Re: Dark Screen Shadow Spots

Postby Resist58 » Sat Oct 02, 2010 9:51 am


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Re: Dark Screen Shadow Spots

Postby Bubby » Sat Oct 02, 2010 12:08 pm


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Re: Dark Screen Shadow Spots

Postby Resist58 » Wed Oct 06, 2010 10:13 am


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Postby raeshao » Fri Nov 05, 2010 9:22 pm

<duplicate post>
Last edited by raeshao on Mon Nov 08, 2010 5:18 pm, edited 1 time in total.

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Re: Dark Screen Shadow Spots

Postby raeshao » Sun Nov 07, 2010 6:37 pm

Well hello there. After searching online for a few hours, I finally found a couple people with the same issue I'm having. I had a tech out yesterday to replace a faulty DMD chip (stuck mirror / white spots), and he knew what he was doing as he'd done it a few times before. So the white spots are gone, and everything looks great except for this new issue. Gray blobs in deep shadow areas, and in shadow areas that aren't so deep, but are uniform. Sucks.

After researching I thought it could be a thumbprint on the DMD, or somewhere early in the optical path. During installation, the tech blew on something... I thought maybe directly on the new chip after taking it out of the bag, but I can't be sure. Again, this only shows up on darkened areas, and overall I get the sense that the black level of the tv is raised from before, although that could also be a settings issue.

Hopefully we can get this figured out. I'll start a thread on the AVS forum linking back here to see if anyone there has a fix. Images brightened some to show cloud pattern.


Last edited by raeshao on Mon Nov 15, 2010 2:49 am, edited 1 time in total.

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Re: Dark Screen Shadow Spots

Postby Bubby » Mon Nov 08, 2010 4:43 pm

Common denominator here is we all blew and stirred up some dust that is in the path of the optics apparently.

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Re: Dark Screen Shadow Spots

Postby Resist58 » Fri Nov 12, 2010 12:36 pm

I am very glad I started this thread and find out I was not alone in having the same issue. I just hope there are enough of these TV's out there still working, so we can get to the bottom of this.

It's looking more and more like (as I initially thought),the use of canned air caused dust or debris to settle on some part of the optics. It could possibly be the light tube that is directly behind the color wheel.

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Re: Dark Screen Shadow Spots

Postby Resist58 » Mon Nov 15, 2010 1:17 am

Just purchased a pdf form of the service manual online. I found an entire page that might fix our problem. It suggests blowing out the light tunnel, (located behind the color wheel), and states that then it should be reinstalled in reverse. This is because dust can settle on the rear part of the lens, but any dust on the front gets burned out by the lamp. There are 5 screws that hold the light tunnel in place.

I may attempt at taking my TV apart again to try this. I had suspected this part had dust on it all along, caused by the can of compressed air I used.

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Re: Dark Screen Shadow Spots

Postby raeshao » Mon Nov 15, 2010 2:48 am

Thanks for looking into this further. It's a pretty rare issue. I was planning on pulling the light engine out this weekend but didn't have time. Please let us know how it goes when you're able to work on yours again.

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Re: Dark Screen Shadow Spots

Postby Resist58 » Fri Dec 17, 2010 2:04 am

I still haven't gotten around to trying this fix. Guess I'm hoping someone else will first.

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Re: Dark Screen Shadow Spots

Postby Resist58 » Tue Jan 25, 2011 3:36 am

A few nights ago I turned on my TV and the picture scrambled and then went dark. The bulb was still working and there was audio. Usually when this happens if I unplug the TV, plug it back in and turn it on, it usually fixes itself. Didn't work this time, so I ended up leaving the TV unplugged for around an hour. Then when I turned it back on the picture was back. I fear though that my HLN617 is having DMD board issues and will soon be beyond repair, as there are no DMD replacement parts for this model.

I really like my 61" DLP TV and don't look forward to buying a new TV. Although having more inputs would be nice. I'm just not sure what TV technology to try next. I would prefer something that consumes less power than my Samsung, yet has at least a 61" screen and not cost me an arm and a leg.

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Re: Dark Screen Shadow Spots

Postby raeshao » Tue Jan 25, 2011 3:57 am

Sorry to hear that. As these sets get older, they can fail in numerous ways. As for mine, the clouds have almost completely gone away. I'm not sure if it was dust, or a thumbprint that evened itself out due to the heat of the chip, or what. There's only two ever so slightly noticeable dust discs that can be seen if you really look for them against a black screen. One other thing that could be at work is the lamp may be dying. I tried calibrating it with the Spears & Munsil bluray, and was unable to get any of the test patterns used for setting white and black levels to show up correctly. And deep black is more of a uniform dark grey. So for now I set it mostly by eye and it looks better than it did.

I had an issue where there was no audio when I turned it on the other night, but all was fine once I unplugged it for a couple minutes. Would a symptom of a failing bulb show up as not being able to correctly produce very high contrast test patterns? Either that, or something is being truncated by using component instead of HDMI.

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Re: Dark Screen Shadow Spots

Postby Resist58 » Tue Jan 25, 2011 9:26 am


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Re: Dark Screen Shadow Spots

Postby Resist58 » Sat Oct 29, 2011 11:06 am

Well my TV is still operational. I haven't gotten around to cleaning and flipping that light tube though.

Still having the issue when if it's not used for days at a time and then turned on the screen will be black or scrambled. If I unplug the TV for a few minutes and plug it back in then it seems to work fine. I bet the DMD board is the problem but I can't find a replacement. I'm hoping to keep this TV working for another few years, because it still shows a great picture.


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