Rear Projection: How Do I Cure The Bad Picture On An Old Unit? (1 Viewer)

[Mike.Thompson]

Ok. So we have the first rear projection TV sitting in our garage. It is probably 10 years old, maybe 11 or 12. Anyhow it is from the early 90's, and I would like to start using this TV as a gaming tv for the original nintendo and atari and super nintendo and all the old systems that dont get to sit next to the new tv. my problem is the picture isnt great at all- I sat for an hour trying to adjust convergence and color and sharpness ect. but to no avail. Everything has sort of a 'Halo' around it, and in general things are just very fuzzy. Is there a way to manually adjust the tv on the inside? I have a good background in electronics, but havent tinkered with tvs much. I didnt want to just open it up and start playing around and make it inoperable. I tried searching for a similar question in a thread, but couldnt find one. If anyone has any websites, or links or useful info I would really, really appreciate it. Take care all. Mike

 

[ken thompson]

I'd try cleaning the lenses. After 10 years or so there is probably an inch of dust on them.

 

[Allan Jayne]

Forget it. The tolerances for convergence and geometry back then were much less precise compared with now. For example it was unusual to have more than 25 convergence points (a 5x5 grid) where there could be an incorrigible two scan line discrepancy between the convergence points and worse at the screen corners.

Add the aging of components to the mix and getting convergence right is even more difficult.

Even in video game arcades I see convergence errors that make text hard to read.

Video hints:
http://members.aol.com/ajaynejr/video.htm

 

[Mike.Thompson]

Ken- Thanks for the reply. I figured this was a good place to start. I will go clean the inside out throughly right now.

Allan- I thought this would probably be a pretty big challange, but I am up for it. I dont expect superb results, but I would like to do what I can to rescue the tv from storeage. Thanks for the link, I will check it out.

Thanks the both of you for the replies- anyone else have any input? Mike

 

[Trenton McNeil]

You may also want to clean the INSIDE of the display screen. I had an old Mitsubishi 50" (had a wood case, and cabinet style doors that closed in front of the tv...weighed a LOT!!!) that I bought used, and after cleaning the lenses and the inside of the display screen, it was almost...bearable! This was before DVD....but LD looked pretty damn good on it.

 

[Kevin P]

What brand of TV is it? Some models (Magnavox comes to mind) had problems with the CRT coolant getting cloudy over time (due to contamination or bacteria growth). If this is the case with your set, it would require the CRTs be disassembled, cleaned and the coolant replaced, not a task for the squeamish.

Otherwise, it's probably a build up of dust on the lenses, plus it's possible the electrostatic and mechanical focus is out of whack as well.

Even in video game arcades I see convergence errors that make text hard to read.

But then how many arcade owners/technicians bother to converge the RPTVs in the arcade games? A lot of them use Mitsubishi RPTVs by the way, so they can be tweaked.

KJP