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LCD Rear Porjection Discoloration


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5 replies to this topic

#1 of 6 OFFLINE   Paul D G

Paul D G

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Posted December 17 2011 - 07:36 PM

I'm thinking I know the answer but I'll ask anyway.


A couple of weeks ago I was watching a B&W film and noticed the bottom inch or two of my Sony KDF-55WF655 Grand Wega has a purplish tint. It's not as noticeable watching in color, but it's still there.


I'm not sure how this happened. We have a PC hooked up to it and it's roughly the height of the browser footer when it's full screen, but we don't use it enough to have caused a burn in.


What can cause this and is there anything I can do to repair it? Could it be as simple as replacing the bulb? The unit is six + years old and we've only had to replace the bulb once. I've noticed the picture is a tad dark and am thinking of getting a new bulb for standby.


Is there some way or resetting the unit via the service menu?


I'm thinking I'll need to have it serviced. Honestly, I'd prefer to get a newer TV. This one doesn't look near as good as the ones currently available. Doubt my wife will go for it, tho.


It's not a big deal and I rarely notice it, but I know it's there and it bugs me. :)



#2 of 6 OFFLINE   Michael TLV

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Posted December 18 2011 - 04:30 AM

Greetings It's called polarizer failure. There are three color plates in the projector light path. red/green/blue ... made of organic compounds. Turns out that they react to the hot light that pass through them and the blue plate breaks down faster than the the other two colors. The breakdown of the blue is not even across the image ... happens in the center faster than on the edges. Over time as the blue goes away in the center, the image turns more yellow ... and the less degraded edges look purple. The plates need to be replaced. In front projectors, the plates cost $120-150 each ... (Also happens way faster on front projection units ... well within the first 1000 hours of wear) This of this like brakepads wearing out. You cannot reset your car and the pads are like new again. Regards
Michael @ The Laser Video Experience
THX Video Systems Instructor/ISF Instructor
Lion A/V Consultants Network - TLVEXP.com


#3 of 6 OFFLINE   Steve Berger

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Posted December 18 2011 - 06:10 AM

Sony was replacing the optic blocks under an extended warranty. Towards the end of the coverage, they were just replacing the TVs since it appears they ran out of the parts to rebuild them. Sony talked about replacing the parts during the initial training classes on the LCD RPTV sets, but then refused to supply any of the individual components and insisted on service at the block and board level. The cash flow amounts pretty much eliminated all the small authorized service companies.

#4 of 6 OFFLINE   Paul D G

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Posted December 18 2011 - 07:37 PM

Thanks for the comments.


Directing towards Michael's - that doesn't seem to be the case here. The only time it's noticeable is when watching B&W programming, or muted colors. B&W image appears purplish at the bottom of the screen, and muted colors appear washed out slightly in the affected area. Vivid colors appear normal. For example, the game show Jeopardy, which is extremely blue in it's color scheme. There is absolutely zero problem with the picture.



#5 of 6 OFFLINE   Michael TLV

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Posted December 19 2011 - 02:46 AM

Greetings A brake pad could be 1% worn or 50% worn. It is still worn and you something you can't stop. You can see it on b/w material first because that is the easiest place to see it. Are the plates completely worn out ... I didn't say that at all. The image will look really green when that happens. Regards
Michael @ The Laser Video Experience
THX Video Systems Instructor/ISF Instructor
Lion A/V Consultants Network - TLVEXP.com


#6 of 6 OFFLINE   Paul D G

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Posted December 23 2011 - 12:46 AM

It was a LOT worse last night. I was watching a documentary and when a scene went to B&W there was a huge blue area on the left side of the screen. When it went back to color I could still see it. Not completely noticeable, but like I said, once you know it's there...


I'm just saying, Michael, that the description you gave didn't seem to entirely match with the problem I was seeing. But it's clear that's what the problem is now.


Hopefully there will be some good deals come January!