Question about RCA Projection Televisions
I have a HDTV RCA and it will power off and restart itself after just a few second, can you help me determine what could be causing this.
Posted on Mar 21, 2013
You may have a dirty or blocked mirror. You can usually take the back off and clean them. If you don't feel confident about it, a repairman can do it for you. If you clean it yourself, I recommend using a good quality glass cleaner and any type of towel that doesn't produce lint. Coffee filters work very well. Don't leave any streaks!
Posted on Oct 21, 2007
This is your mirror tunnel. Light passes through the mirror tunnel to the DLP. The tunnel is made up of 4 mirrors glued together. Over time the glue comes apart and the tunnel shifts.
It starts out like this: |_|
and when the glue breaks down it does this: \_\
So the light, instead of passing through the mirror tube, goes through the ends of the mirror, so you get SOME light but not all.
I contacted RCA and they said:
"Ok, well sadly they do not offer the light tunnel anymore, which is what you need. Sadly you would be rendered to get a whole new light engine assembly. That would be the D.N.D module, light tunnel,color wheel,optic spanner, and oci. mirror. Your best bet would be to search ebay for a broken engine and replace it that ways. "
Awesome support! NOT! (That is the actual full text of the message from RCA support.)
I have some high temp epoxy and will be attempting to re-glue the parts myself.
Posted on Mar 22, 2010
It's the light tunnel. The tunnel is a square tube made up of 4 mirrors glued together.
It looks like this from the side: |_| (with a piece on top too.)
When the glue breaks down, it shifts inside the little mirror holder. The shifted mirrors looks like this /_/ what you are seeing is the shadow of the tilted mirror tunnel.
ON the RCA's there's not a good fix.
"Ok, well sadly they do not offer the light tunnel anymore, which is what you need. Sadly you would be rendered to get a whole new light engine assembly. That would be the D.N.D module, light tunnel,color wheel,optic spanner, and oci. mirror. Your best bet would be to search ebay for a broken engine and replace it that ways."
That is the ONLY response I got from them.
I took the set apart and found the 4 tiny mirrors. I will be attempting to epoxy them together. (The set is dead anyway, why not try?)
Posted on Mar 22, 2010
I had the same problem on my 50" DLP. Today I took the light projection mechanism apart to get to the
mirror tunnel (a piece about 1.5" long located between the projection bulb
housing and lens housing) and, for now at least, the shadow problem has
been corrected on my TV.
It would be difficult to describe in detail without photos of how to remove the mirror tunnel. Briefly, once the lower rear cover is removed, it involves completely removing the entire assembly of the projection bulb and lens, along with disconnecting 3 or 4 cable connections. This assembly is held in place with 3 large screws around the projection lens housing in the lower center of the TV. After it's completely removed from the TV, removing smaller screws will break down the component parts. Once you locate the color wheel (about 2" in dia.) between the bulb and lens, the mirror tunnel is directly adjacent to it.
Handle it all with care, and I strongly suggest that you immediately cover the protruding projection lens will a lens cleaner cloth (held by rubber band) so it doesn't get scratched or smudged while you're working on the assembly. This will all make more sense after you get into it. Just remember where everything goes, both cables and screws!
My four mirrors had indeed shifted into a flatter parallelogram than it should be. On my set the metal tunnel casing is molded so that it doesn't allow for the mirrors to be in the shape of a rectangle; it requires a parallelogram shape. The mis-shapened tunnel caused a small portion of the metal mirror housing (on the lamp end) to protrude into the interior of the tunnel, hence the shadow on the screen.
To re-shape the mirrors I gently inserted a nylon cable tie--with a sharpened leading edge--into the tiny gap behind the mirror that had shifted. In doing so the mirrors shifted back to the proper positions and stayed there when I removed the cable tie. (Be very gentle with the mirrors and do not insert anything into the tunnel!)
It's not clear why this (now restored and larger) gap behind that one mirror even exists, but to ensure the the mirrors don't shift again, I inserted and left in a length of cable tie (which is near perfect in thickness and width) in the gap. Time will tell whether heat will deform it.
Perhaps a similar-size strip of metal would be better but I didn't have one. And I would not use any kind of glue or adhesive on these mirrors (as others have suggested); with their small size and the need to keep them crystal clear there is just too much potential to royally mess them up.
After putting it all back together and testing, the shadow is gone. Hope this helps and works for others!
Posted on May 03, 2010
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