CRT geometry issues on a JVC AV-27230

[Mrx3750]

I found this TV a few weeks ago on trash night. Fixing its main problem was easy enough. Bad cap near the flyback was causing the G2 to be way too high, causing retrace lines. Changed it, and a few other USL branded caps near the vertical IC since those can also be a problem with this model.

The TV is a cheap, low end model, but it has Component video, and that makes it useful enough to keep around. The picture is acceptable now, but it has a problem that I see alot on cheap CRT TV's:



The JVC is in the middle. To the left and right are two older, and much better built TV's. Notice the sides of the image on the JVC. They're bowed like a fishbowl, while the two TV's I was comparing it to are relatively straight.

Now the JVC has a straight image when that image is dim, and the bowing happens when the brightness of the image goes up. The brighter the image, the higher the distortion. Now, this is a fact of life with CRT TV's I know. They all do this to a degree, but I'm wondering if I can reduce the bowing somehow?

[RON_CET]

Re: CRT geometry issues on a JVC AV-27230

Was one of your capacitors you changed C581? Also would be interesting to know during your brightness changes hang meter on TP91 or positive side of C525 and look at the 134v dc (use TP-E for live gnd or negative side of C525) this model doesn't used pincushion correction circuitry.Note!! your 134v should stay steady during brightness changes.

[Mrx3750]

Re: CRT geometry issues on a JVC AV-27230

Don't really know. Spotted a bulged cap near the flyback, a 10uf@ 250 volt, and changed it. It was a USL branded cap with a weird vent pattern identical to some samsung capacitors I have. So I hunted down some other caps on the board with that same vent pattern and changed them out. At least one near what I believe is the vertical IC tested low. Replaced it with a good Nichicon.

There isn't much to this chassis board. What could be the causes of this bowing, and what could I do to fix it? Because if I'm going to open this TV again, I'd like to check for everything it could be rather then post here and play trial and error.