Hello

I was given a Panasonic TV model TX-29AS10F chassis EURO-4H flat tube
with a purity problem, a discoloration visible on top left and right.
After trying to adjust the purity rings, yoke position and making sure
it was not a magnetization problem, I concluded it was a defective
mask, the set was likely dropped. I have spent some time playing with
magnets around the yoke, the defect can be corrected quite easily with
some magnets but after a degaussing cycle, part of the discoloration
returns no matter how near the yoke the magnets are placed. Also, too
near to the yoke and the geometry and convergence are affected.

But almost casually I found that I can magnetize the tube in a way
that the picture is perfect without adding any magnet, the only
drawback is after a degauss cycle the problem returns, but I
disconnected the degausser to fix that. It's been some days and the
picture is still perfect, as long as the set is not moved it looks
like a good solution. This set weighs like hell to be moved anyway.

To magnetize the CRT I use a big speaker magnet, put near the
discoloration on the back of the tube and then move it away slowly. As
I'm moving it away all the funny colours go away including the
original discoloration - got it perfect!

I thought I would share this experience as it saved an otherwise bad
tube, at least for now.

That's good info! I have a similar scenario. Sony 32" Wega TV, was
dropped, & shadow mask inside the CRT has shifted.
I unplug the degaussing, right after it finishes, & place magetron
magnets (from a microwave magnetron...cut in half), on
top of the set, close to the top, & adjust, or flip as necessary.
Occassionaly I adjust as necessary. Works fine & it's a sin to toss
out a Sony! Dani.