Attention LCD Owners: Fix Your Color Uniformity Problems by Cleaning! - AVS Forum
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post #1 of 132 Old 08-23-2005, 04:53 PM - Thread Starter
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For those of you out there with LCD projectors that are getting along in age and are starting to show color uniformity issues this thread might help you out! I totally psyched about my results.

Some background...
I've owned my Panasonic L300U (same as AE300) for about 2.5 years now and use it a fair bit. On a recent check I was at 2536 hours of my first bulb. This projector (knock on wood) should last until 5000 hours. Over the years I've developed a few dust blobs and have opened my projector once to clean them out with partial success.

Well, within the last year or so I started to develop a bad color uniformity problem seemingly overnight. It wasn't as bad as the picture shows below, I think that is partly a trick of the camera to saturate the pink tint more than it really is. However, it was bad and did get worse over time. Of course, me being an AVSer, I noticed it right off and it really kept me from enjoying the movies on occasion (bright, uniform scenes in particularly snow, sky, etc). No one else really noticed or at least they didn't care enough to comment.

Here is a picture from before the surgery the projector is just showing an all medium grey image. Again, I purposely shot it so the pink would show up, it's not that bad in real life... but it does suck:

So, what is the problem It must be those dreaded blue polarizers right? I've read the TI white paper, I know LCD sucks and has a short lifetime I assumed I was screwed and just lived with it for the last year or so just waiting for the day I could afford a nice LCOS or 3-chip DLP (I'm bothered by rainbows). Then I cam across this thread: http://www.avsforum.com/avs-vb/showthread.php?t=559557 Post #10 in particular was intriguing to me as they said they cleaned off the polarlizer and the pinkish tint went away! Hmmm I called the Panasonic repair shop to see what I was up against. If they cleaned it out for me, it would be a minimum $100 labor, plus $30 return shipping, plus shipping it to them (maybe $25?). If the polarizer was bad, I would have to pay to replace it (another $100). So I was looking at minimum $155, maxwho knows. I decided to give it a try doing a deep clean myself, if I screwed things up I could always send it in anyway

So I took it down from the ceiling mount and opened it according to these instructions (in the quote box): http://www.hometheaterforum.com/htfo...51#post2248651 I didn't take the whole thing apart but I did undo the ribbon cables coming from the LCD imagers, as well as taking off the PCB board on top of the optical block. After a thorough de-dusting, I went in for the polarizers. First the blue

My first thought was, THIS COSTS $100!!!! It's just a little piece of plastic. Anyway, I checked it in the light

It seemed ok hmmm Oh well, I dusted it off anyway. On to the green polarizer

DING, DING, DING!!!! Clearly this was the problem. There was actual dust built up right on the polarizer! I always figured the dust would be on the LCDs.

It's clearly in the same pattern as the red tint on the screen too. Well I dusted it off thoroughly. The red checked out ok. Same as the blue. So I finished blowing the dust out and put it all back together. When I remounted it and turned it on this is what I saw. I included a before and after so you can get the full effect!

BEFORE...

AFTER...


YEAH! The moral of my story is if you have an LCD projector, and you have crappy color uniformity it might indeed be the dreaded blue polarizer or it might just be some dust! Open it up, blow it out, good as new. If you don't have an Lx00u, you should still be able to find a service manual online or buy one from ebay. Enjoy.
-Matt

P.S. I take no responsibility for anyone breaking their projector trying to dust off their polarizers... proceed at your own risk
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post #2 of 132 Old 08-23-2005, 06:06 PM
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what did you use to remove the dust? just regular canned air?

Mike
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post #3 of 132 Old 08-23-2005, 06:10 PM - Thread Starter
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Yes, compressed air... I think it's just CO2. Becareful to tilt the projector to the can, not the can to the projector or you'll end up with frozen liquid shootting out which could damage the polaraizers or LCD panels.
-Matt
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post #4 of 132 Old 08-23-2005, 06:11 PM
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Sweet. I went through the same procedure. My pink 'haze' was a little more spotty as the dust came in larger clumps! And I have the most dust on green, too. I was so sure it was either a polarizer or panel I didn't take any picture. Thanks for posting your pictures.

The blue polarizer does look to be showing early sign of some fading, or is it just my monitor? Another theory of mine is that dust helps trap heat so cleaning the polarizers and panels and prolong their life.
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post #5 of 132 Old 08-23-2005, 09:04 PM - Thread Starter
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Quote:
Originally Posted by rickster904 View Post

The blue polarizer does look to be showing early sign of some fading, or is it just my monitor?

Good catch... I didn't think it showed up in the pictures, but you are right. There is a faint burn in the blue polarizer. The only reason I didn't worry more is that there seemed to be a similar discoloration in both the green and red polarizers as well. They are all very, very faint though. I'm sure it's not good for longitevity but as long as they are are going at the same time

Anyway, I hope they last another year or so when I'll be moving next and can upgrade. For now, I'm really pleased with the results! Glad to hear similar successes.
-Matt
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post #6 of 132 Old 08-23-2005, 09:11 PM - Thread Starter
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Quote:
Originally Posted by rickster904 View Post

My pink 'haze' was a little more spotty as the dust came in larger clumps!

Interesting... Did it look like a dust blob on the LCD... only pink? I had dust blobs in the past but they usually showed up on black or dark backgrounds and showed up as green or blue blurry circles. I never considered the pink tint to be dust because it was so wide spread and relatively uniform. I guess I read so much about how crappy the blue polarizers were in LCDs that assumed the worse. I even swore off buying LCD projectors for any future upgrades but I may have to revise my story...

What was it that Epson was going to do in their new generation of D5 LCDs... I remember reading about an inorganic layer. Was that on the polarizer or the LCD itself?
-Matt
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post #7 of 132 Old 08-23-2005, 09:39 PM
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Nice job!

regards,

Li On
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post #8 of 132 Old 08-24-2005, 12:41 AM
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Wow! thats good to know, but is there a way to clean them from smoke haze?
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post #9 of 132 Old 08-24-2005, 08:48 AM
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Well I just did this on my 300. The only thing I found was that you have to undo all the connections on the board except the white ribbon. I removed all polarizers(one at a time) and they were all quite dusty. I used compressed air but also had to wipe them off with a cloth as the compressed air would not remove all the dust. I didn't have a problem with color uniformity but thought a good cleaning was in order. Put everything back together and fired her up...looks ok, ie. didn't screw anything up. Total job time about 1/2 hour.

The hardest part was getting over the fact that I know next to nothing about electronics and the thougth of pulling apart my favorite toy was a little unnerving.

Other areas of interest

http://my.T-Nation.com/scotty144

ClubWrx.net Scotty144
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post #10 of 132 Old 08-24-2005, 04:47 PM
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Good Job Matt!!

Can you catagorically say that your PQ and colours have not been adversely affected by the removal and re-insertion of your polorizers? If you can say with certainty that there where no adverse affects, then I think we can put the myth to rest that the polorizers are very position sensitive down to the micrometre. I was sure I read somewhere here that someone else who removed their polorizers screwed up their colours and had to make many fine adjustments to the polorizer position/orientation before he got his colours back perfect.

One less thing to worry about so, and I think I'll add this step to my PJ cleaning regimen. Another benefit off the removal of the polorizers is that it gives great access to the back of the actual LCD panels. Don't think there is anything we can do to improve access to the 3 faces of the prism block and the front side of the LCD panels unfortunately.

Coming up on 5000hours on my second bulb soon (4450hrs atm) so I think thats when I'll do my next cleaning session when I put the new bulb in.

Did a forum search under my username but can't find my cleaning guide from a year or two ago. That only documented taking the mainboard off and dusting the panels though and I didn't even document all the steps with pictures either. This time I'll do a full step by step guide, fully documented with pics involving taking the mainboard off, taking the polorizers out, removing the entire optical assembly, cleaning all three fans and clearing the dust bunnies out of the air ducting, and de-dusting of the polorizer, LCD panel and Prism block surfaces.....oh and how to put it all back together!!

I promise it'll be easy to follow and will take much of the stress out of the project for other people. Like Matt said, if you can change a graphics card in a PC you can do this.

Heres the first draft:



Only joking

Anyway should have it done in a few weeks and hope it will be an asset to the AE300 community


Oh... and I'll post a pic of the worlds first 10000hr AE300!
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post #11 of 132 Old 08-24-2005, 05:11 PM
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Quote:
Originally Posted by calibos View Post

Good Job Matt!!

Can you catagorically say that your PQ and colours have not been adversely affected by the removal and re-insertion of your polorizers? If you can say with certainty that there where no adverse affects, then I think we can put the myth to rest that the polorizers are very position sensitive down to the micrometre. I was sure I read somewhere here that someone else who removed their polorizers screwed up their colours and had to make many fine adjustments to the polorizer position/orientation before he got his colours back perfect.

Well I took out my polarizers and blew them off with compressed air and just reinstalled then with alignment by eye - noted how the screw that fixes them was sitting on top of the slot before, and re-did it afterwards. No critical alignment performed. PJ still worked just as before with no negative effect on picture quality.

I've seen the light... and its "White 255"!! (or is it 235?)
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post #12 of 132 Old 08-24-2005, 05:16 PM
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Just for any of you who have a colour tinge top and bottom... blue along bottom edge and yelowish on top edge... I had this and had Panasonic here have a look at it. They had to "re-seat the PBS array". This completely fixed the problem. The PBS array is the "polarising beam splitter" and I understand it is the large lens thing that sits closest to the lamp. The light passes through this first. The tech said he had seen a few with this problem and the PBS seems to move out of alignment for some reason - maybe heat -. Any way it was fixed without needing parts.

Also regarding the failure of the blue polariser. If you look at where it sits it out to the side, it seems that the airflow in the PJ somewhat bypasses it, and hence perhaps it gets hotter - although it is the furthest polariser from the lamp.

Thanks for the tips everyone, knowing that dust on the polarisers can cause the colour uniformity (which I have had as well) is good news and makes me think I'll keep this PJ for a while yet.
JackTaylorWinch likes this.

I've seen the light... and its "White 255"!! (or is it 235?)
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post #13 of 132 Old 09-04-2005, 08:50 AM
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Quote:
Originally Posted by calibos View Post

This time I'll do a full step by step guide, fully documented with pics involving taking the mainboard off, taking the polorizers out, removing the entire optical assembly, cleaning all three fans and clearing the dust bunnies out of the air ducting, and de-dusting of the polorizer, LCD panel and Prism block surfaces.....oh and how to put it all back together!!

I promise it'll be easy to follow and will take much of the stress out of the project for other people. Like Matt said, if you can change a graphics card in a PC you can do this.

Hey, I can do PC graphics cards. I've even done wireless NICs! Looking forward to your post calibos.... errr... Mr. 5000 hour man.

Matt - awesome information too. Glad you got the pink haze fixed and the L300 is looking great again. I'm the one that sent in my Panny for the 1 year cleaning... I'm at 2 yrs 4 months now, no major issues, but I'm going to wait for calibos' guide. That along with all the other great info that was posted and I'm going to try this myself. If I muck it up, I too will have the fallback of sending it in.
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post #14 of 132 Old 09-04-2005, 04:16 PM
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I'll do my next cleaning(and document it with photo's) when I have some spare time or when I put the new bulb in. Whichever comes first. I'm at 4600hrs atm so it'll be about a month at the latest.
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post #15 of 132 Old 11-11-2005, 04:48 AM
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Hi All... I had posted on another thread but this is obviously the more apprpiate one so I'll repeat it here: My L300U is on it's second lamp... Lamps #1 & #2 have both exceeded 5000 hours. I already have a third lamp ready to go in but have not installed it yet. Am I tempting the devil by continuing to run the old lamp? Anyway, I have dark discoloration on blue screens that shows up as a yellow discoloration on light scenes. It is dead-center of the image. I guess this probably indicates actual burning of the blue polarizer that cleaning would not remedy? i.e. It would need replacing...? Also, I went to Panasonic's parts order page and it showed "no parts listed" for my input of PT-L300U nor was it able to find the part # for the blue polarizer. Have they stopped supporting the 300 or am I screwing it up somehow? I ordered my Lamps through the site but you never know what kind of Brain Drain I may suffer at any given moment! Great Info on disassembly and cleaning... etc. Thanks all! I wonder what would be the effect of running without a polarizer or the chance of getting filter material to replace the actual plastic filter in the existing frame?
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post #16 of 132 Old 11-11-2005, 07:43 AM
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try ptl300u, without the dash. part num is:TENC0145 POLARIZING PLATE/IN (B) 93.00

Mike
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post #17 of 132 Old 11-11-2005, 06:08 PM - Thread Starter
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I have no idea how their pricing compares but this place sells 481 parts for the L300u... you could probably build one yourself if you wanted. This will at least give you all the part numbers but it maybe difficult to decipher what everything is...

Good Luck
-Matt


L300u page on PartStore
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post #18 of 132 Old 11-12-2005, 12:50 AM
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Thanks Mike, I pulled it up straight away to-nite... Thought I'd tried that... duh...
Hi Matt, I noticed that on the PartStore site there is the TENC0145 part and also another part listed as Plate / IN (B) with a part# of TEFC0145 @ a cost of $53.15 I wonder if this is the filter itself without the metal frame that holds it? I haven't been that deep in my PJ yet to have actually seen the polarizer! Anyone think this is a possibility? I will give them a call and check that out... I will report back here if there is any joy to be found there!
Thanks Again to all...
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post #19 of 132 Old 11-12-2005, 08:14 AM
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Great post. My AE100 is showing these signs so I may take the plunge and break, i mean fix it myself. if it breaks then that new projector i want will be a little closer anyway
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post #20 of 132 Old 11-12-2005, 09:30 AM - Thread Starter
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GutterPoet-
My advice to you would basically depend on A) how much money you are willing to spend, and B) how confident you are in doing some basic dissassembly/reassembly.

The way I see it, you've got 10,000+ hours on that thing... it better be opened soon to clean it out. I'm sure it really needs it by now based on mine at only 2500 hours and others I've heard/read about, some even in the thread above.

Additionally, as mentioned, your main problem is probably a burnt polarizer, which from memory, will cost you $100 or so. However, remember, I thought mine was the polarizer as well and it turned out to be only dust. Granted your pj has 4 times the hours and heat on that polarizer. And if you look at my picture the post at the top... there is a faint discolorization in the blue polarlizer so I'm sure mine will eventually get worse/noticable as well. Basically, you never know until you open it up. And I wouldn't bother ordering a new part until you know you need it. I wouldn't worry just yet about the exact model number... we'll help you find it if it comes down to that.

Recommendations:
1) Easy but more costly - Ship it to Panny, tell them it needs a deep cleaning and a new polarizer. It will cost you $20 to ship it to them, they'll charge $100 minimum to open it/clean it, they'll charge you $100 for the part (if it's needed) and then another $30 to return ship it. You'll have a nice, clean projecter with no hassel to you for about $250.

2) Do what I did - Open it, poke around, see what you see. Maybe it's just dust. Clean it up (take pictures as you go for us folk) and put it back together. Either you'll have fixed it and your done or... you realize you need a new polarlizer and you can do it yourself for $100 or go back to rec 1. The whole process was well under an hour for me and only set me back 1.5 cans of compressed air. If it was the polarlizer, you clearly made it this far so you should have no problem re-opening your projector after your replacement part arrives and swapping out the bad one. So this option will likely save you $150 if you DIY.

So what is your time value of money? If you are risk averse, $150 might not seem like much to know the job is being done by professionals who are responsible for returning your projector in working order. Heck, it's cheaper than a bulb! Or you might balk at that cost for a simple cleaning and plastic replacement piece and decide to do it yourself. That is what you need to decide, however, I completely understand that it's not for everyone. I was pretty nervous the first time... now, though, I would do it again in a heart beat if it needed it.

I hope that rambling helped.
-Matt
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post #21 of 132 Old 11-12-2005, 10:40 AM
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I remember taking my first projector apart a few times to clean out dust. When I got my Panny PTL75u (LCD business projector used for HT) and then my Z2 I put a pre filter over the air intakes. The filter is an Electrostatic Hammock filter (True Blue Company LaPorte Indiana www.trueblue.com). It looks like white cloth and is supposed to remove dust, pollen, pet dander, bacteria and smoke. 1 year on the 75u and 2 years on the Z2 and not a spec of dust on either and none of the problems reported here. Never had to clean the Z2 because of dust on the panels. I smoke, but it looks like the smoke accumulated on the pre-filter as there was zero discolouration of the Z2's filter. It looks like new and I have never replaced it. However, I only have 1,000 hours on the Z2.
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post #22 of 132 Old 11-12-2005, 08:55 PM
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Thanks Again Matt, I will take your detailed and sage advice and dig up the camera so I can take pictures too! That trueblue filter sounds like the thing for me... another smoker...
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post #23 of 132 Old 01-02-2006, 10:41 AM
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I also experienced a pink uniformity color issue on the bottom right corner and proceeded to open up the panny and blew out the whole projector plus the polarizers which were quite dusty only 600 hrs on the panny. NOTE: did not remove the polarizers only blew them out with compressed air from radio sXXXX velocity compressed air. and after putting it back together and testing with march of the penguins, all pink tinge uniformity issues have been removed with a simple 5 dollar can of compressed air... THANK YOU mpjohnst YOU ROCK !!!
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post #24 of 132 Old 01-06-2006, 03:10 PM - Thread Starter
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Another satisfied customer!

Honestly, I've recieved soooooo much valuable information on this forum over the years that I'm just glad I could give a little back. Enjoy your new dust free 300u.
-Matt
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post #25 of 132 Old 01-22-2006, 11:16 PM
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BUMP!! Any chance we can see the initial pics??
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post #26 of 132 Old 01-22-2006, 11:48 PM - Thread Starter
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Hmmm... my computer at work must be down. That is where they are hosted. I'll try to check into it tomorrow. Maybe I'll move them to Imageshack.
Sorry.
-Matt
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post #27 of 132 Old 01-23-2006, 08:05 AM
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I have opened up my 300U several times and use a large pipe cleaner to help dislodge the dust without removing the circuit board. Perhaps I will do that next time I clean the projector. For some time I have noticed a faint line of discolorization on the top of the red screen when in service mode. This is only noticeable on bright scenes and then only slightly. I have wondered if this was caused by a line of dust or some form of misalignment. I now have 1150 hours on the original bulb. I average about three hours per on cycle.

Great information on this post.

Tom
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post #28 of 132 Old 01-23-2006, 11:58 AM - Thread Starter
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Images have now been rehosted on Imageshack...
-Matt
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post #29 of 132 Old 01-23-2006, 12:04 PM - Thread Starter
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Quote:
Originally Posted by Thomas Willard View Post

I have opened up my 300U several times and use a large pipe cleaner to help dislodge the dust without removing the circuit board. Perhaps I will do that next time I clean the projector. For some time I have noticed a faint line of discolorization on the top of the red screen when in service mode. This is only noticeable on bright scenes and then only slightly. I have wondered if this was caused by a line of dust or some form of misalignment. I now have 1150 hours on the original bulb. I average about three hours per on cycle.

Great information on this post.

From what I have read, if there is a clear line across the top or bottom, it might be your PBS array (see gazzagazza's posts above). Then again, what do I know... all I did was blow out some dust

If it is the PBS array, it seems like something you could do yourself if you are adventurous. It might be worth contacting calibos via PM. He posted a pic above with his unit totally dissassembled. If he has done another deep clean since posting, he might be able to offer you some detailed instructions...
-Matt
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post #30 of 132 Old 01-24-2006, 05:31 AM
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mpjohnst:

When I say line, it is not a sharply defined one but rather fuzzy on the edges. At least it is not getting any worse. When I first noticed it, I went to high fan and perhaps that is why it has not degraded any more. No problem with the blue or green screens when in service mode.

Tom
Thomas Willard is offline  
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