Problem with CRT rear projection HDTV

[Shawn]

My roommate has an RCA r52wh77 52" CRT Rear Projection HDTV that we have in the living room. Basically he bought it broken for cheap. It looks like it was dropped.

I've been messing with it for the past month trying to improve the picture. At first I only played with the service adjustments and tried to compensate for the messed up screen. I finally took it apart and fixed the screen, which had been knocked out of position which caused it to be wavy and not flush. I ended up fooling with the lens focus (both manual and digital) and the color saturation. I probably shouldn't have touched either.

Anyway, it seems like I made the original convergence problems worse. I don't know if it was something I did inside the set, or something I adjusted in the service settings but the screen's convergence changes depending on the brightness. It was always like this, but now it's a lot worse.

Here is a diagram of what is happening since this is hard to describe in words:
TV displaying a dark 4:3 image
TV displaying a bright 4:3 image

As the brightness increases, the shape of the image is no longer square. The corners of the screen are stretching. This really isn't that noticeable when watching a 16:9 image. The problem though is that I'll set the convergence and it'll look fine, but as soon as the brightness changes the colors no longer converge at the sides of the screen and it looks pretty bad.

I'm pretty sure it's an ITC222 Chassis.

Any ideas on how to fix this thing?

 

[montypythizzle]

Probably a PSU issue, just my guess.

 

[Modelworks]

Its most likely a capacitor(s) that have become open.
Projection Tv's generate a lot of heat inside the cabinet and its not uncommon to have capacitors go bad.

Your correct in that you should not have touched the convergence or the focus as neither of these are causing the problem.

The problem most likely is in the horizontal deflection circuit or the B+ supply.
If the high voltage drops when its needed to increase for the brighter scenes it will cause the problem your describing.

I don't recommend poking around on the deflection board or the HV area unless your familiar with what your doing. Voltages off the flyback transformer can be 20KV+ and persist even when the set it unplugged.