My Television Picture Was Bouncing

Recently the picture on my television was “bouncing” or jittering up and down. Whacking it on the side or stamping your foot on the floor would make the picture stable again. I began to think that possibly my 9-year-old Panasonic CT-20G21U 20-inch television had come to the end of its useful life. Or at least the effort needed to fix it would be far more than what it was worth. At any rate, with all the foot stamping, I was starting to be reminded of a carnival act in which the horse was supposed to solve math problems.

It had other problems too, like color “blobs” or regions which looked like they were more purple than other regions. I was pretty sure that just meant the tube needed degaussing, but my TV doesn’t have a degauss button, so I wasn’t sure how to do that. Some webpages suggest that you can get TVs to degauss by turning them off or on, or possibly by unplugging them, but that never seemed to work for me. So another problem.

Then I came across the Panasonic TV Service Modes page. On it, the author tells how to get into the super-secret maintenance mode of certain Panasonic TVs, and make adjustments to all sorts of crazy things affecting super-low-level functioning of your television. My model wasn’t listed, but as it turns out, it worked anyway. So I got into “Serviceman Mode”. I quickly discovered that there weren’t any adjustments that I was comfortable messing with. So I exited the Serviceman Mode. On exit, the TV did what looked like a full reset.

Voila! Unexpectedly, the purple blobs and vertical picture bounce went away! My only guess is that the full system reset may have degaussed the set. It’s possible that my set was so magnetized that even the vertical hold was suffering.

So if you have weird problems with your TV set, maybe they can be fixed by degaussing. And if you can’t figure out how to degauss your set, try googling for a way to get into its service mode. (Or its sexist “Serviceman” mode.)

Sci.Electronics TV Repair FAQ by Samuel Goldwasser