In the past year or so I have seen what seems to be a increase in the number of posts & threads on "white dots". As these sets get older, it's not unusual that problem develop. Anyone that goes under the foolish belief that mass produced consumer goods shouldn't break, needs a reality check!
These are nothing but stuck mirrors on the DMD chip itself. They can't be cleaned. The manufactures repair policy usually would be to replace the entire light engine since these shouldn't be repaired in the field due to the lack of a 'clean room' environment, the lack of training and delicate nature of the part. This varies from manufacture to manufacture, but past practice was to swap the LE's and send the 'dud' back to a repair service that specifically rebuilds these assemblies. Members have reported replacing them on their own or having the manufacture replace it if it is under warranty. Just as automobile service shops do with many larger or complex parts, send them back for rebuilding;http://www.avsforum.com/avs-vb/showthread.php?t=926204
A little background for those late comers to DLP's.
DMD's (Digital Micromirror Devices) have been around since 1987 developed by Texas Instruments;http://en.wikipedia.org/wiki/Digital_Micromirror_Devicehttp://www.dlp.com/default.aspx
The following are FAQ's on the principales of DLP (Digital Light Processing);http://en.wikipedia.org/wiki/Digital_Light_Processinghttp://www.dlp.com/technology/how-dlp-works/http://www.dlp.com/technology/dlp-faqs/
Two problems with all of this are:
1. A lamp will eventually need to be replaced. Just like slide, movie, overhead projectors have had for the past 50 years, these 'projectors', any 'projector' that has to have a light source (including CRT's) will eventually need it's 'light source' replaced.
2. Since these are only single chip DMD's unlike three chip front projectors, there has to be a way to produce the three primary colors. This is done with a color wheel which is problem two. It will eventually fail since it is mechanical either do the bearing going bad or the 'vanes' of the wheel breaking and flying apart.
Samsung solved both of the above by introducing a 'LED' driven DLP four years ago, but through their stupidly, yes stupidly, discontinued them in favor of their power hungry LCD & Plasma flat panels.
What is happening is, these "micromirrors' get 'stuck' either in the on position (white dot) or the 'off' position black dot. Off is preferred since it is harder to see a black dot that a white one. Just like 'pixels' on LCD panels get stuck open or closed, the same thing happens here.
I did a search for "white dots" and it returned 500 hits. Some of the more prevalent threads are here;
(Defective Mits thread)http://www.avsforum.com/avs-vb/showt...s#post20168235
(DMD board replacement)http://www.avsforum.com/avs-vb/showt...ght=white+dots
(this example is one of the worst)http://www.avsforum.com/avs-vb/showt...s#post19064778
(well into the owners thread, only certain models)http://www.avsforum.com/avs-vb/showt...s#post19253640http://www.avsforum.com/avs-vb/showt...s#post19250339
(class action suit)