reversing magnet damage to picture tube

[avionic]

I have one set that's either so magnetized or somehow otherwise damaged that even multiple treatments with an external coil wouldn't get it back into line. I'd love to find out how that happened.

A loose shadow mask within the CRT will really foul up the purity and look similar to a magnetized screen.

[marty59]

Maybe the yoke has slid back a bit and needs repositioned.

[jeyurkon]

Originally Posted by avionic

A loose shadow mask within the CRT will really foul up the purity and look similar to a magnetized screen.

The mask is ferromagnetic. With a strong magnet it can be distorted. Or, what you said.

John

[Jeffhs]

My RCA XL-100 CTC185 fell off its stand a few months ago. When I put it back and turned it back on, I saw splotches of color on the CRT screen. The automatic degaussing coil in the set was no help, though it did cycle on and off as it should when the set was turned on. Wondered what was going on for a few days, then I tried moving a speaker magnet around the screen, while the set was on. To my surprise, the splotches disappeared and did not return. The picture now looks every bit as good as the day I bought the set, nine years ago. I mentioned this in a thread on this forum shortly thereafter, and got a reply (among several others) to the effect that the shadow mask may have been bent when the TV hit the (carpeted) floor in my apartment; the external magnet may have repositioned the mask such that it was now back in proper alignment.