Sony 32" TV with colored upper corners

correct link to the picture:

It is quite possible something is magnetized that is not within the area of the internal degaussing coils. Try a strong magnet near the worst corner and rotate it rapidly and continually while moving it away from the set until you can't see any effect of the picture color in the corner, Then move an additional 3 feet away before stopping the rotating. See if that helps at all, then also degauss the set again. Do that degaussing after the set has been idle/off for at least 30 minutes to allow the degaussing components to start cold. I personally always use an external degaussing coil whenever I am at all suspicious about the interrnal cois as they do not put out a really strong degaussing fiield.

Please post the results.

blue:

picture:

That's useful for a test, but anything that puts out a strong *AC* magnetic field, like a soldering gun (not iron) or a bulk tape eraser will work better. The permanent magnet might tell you if there's a degauss issue, but you can't use it to fix the problem. I've actually degaussed CRTs with the above.

Maybe a transformer? I dunno, I haven't tried that....

jak

Arjan

I've had this problem with Sony sets having bad purity on the lower left corner. Moving the set around the room to realign relative to the Earth's magnetic field only helped a little. Yes, in this case, it was the tube, it had to be replaced.

Colin

Arjan wrote:

blue:

Suggest getting the SONY Service literature for the item and then attempt both purity and registration setup. Confirm the arpeture grill assembly is not loose, lightly tapping on the screen while displaying a solid colour.

blue:

picture:

Heh I've used a Weller 140 watt gun to degauss.

I wound my own degaussing coils about 40 years ago. You could see the CRT flicker at 20 feet when it was tuned on, and turned to face the CRT. I make a bunch of them and sold all but one of them. They had 20 foot power cords and a heavy duty industrial chrome push button so you didn't accidentally leave it turned on. I still have the one. they were made with surplus 17 AWG DE/DC magnet wire. They were wound on a plywood jig, then tied off and covered with two layers of 3M #66 electrical tape. The switch was mounted on a curved aluminum plate, wired to the coil and cord, then the plate was over wrapped with more tape.

he

I cannot imagine that the CRT is so magnetized..... The TV did not have this problems when it still was at the owner where I got this TV set from... I only dismounted it and cleaned it with a vacuum cleaner, because it was very dirty and dusty inside. The original problem was that vertical black and white bars were visible in the picture, even without input signal. This was caused by a bad capacitor in the power supply line of the video amp. But after replacing of the cap it turned out that the corners of the picture where colored.... Can it be a loose contact somewhere from a coil? I checked all the plugs and they are all fitted OK. It was maybe a good idea to turn the set on before dismounting.... Transportation went without problems, the set was not put down very hard. I moved the set around the room, but the color spots are still there.....

The tube can pick up enough residual magnetism to cause your problem simply from being moved. They are very sensitive this way (the Earth's magnetic field is the cause of this phenomenon) but in case it wasn't mentioned earlier, make sure there are no speakers near the TV.

It's also possible that the degauss circuit has failed or a correction magnet has fallen off the tube, or somehow the purity rings got jostled.

Mark Z.

Wow I bet those kicked some ass. I bought one in the mid 70's from a friend who did RCA repair. It was one of the good old ones and I still own it although I haven't used it in some time.

I'll post some pictures when I dig it out. I've forgot how much copper it has. You could not only degauss a TV set, you could demagnetize hand tools, and wrist watches. :)

I use a degaussing coil I salvaged from a junk TV and put a power cord on. It gets hot in a hurry, two in series and attached together would probably be a better idea. You can bundle them into a more compact circle than they were originally.

I think I used 200 turns of 17 AWG on a 12 inch form. It HAS been almost 40 years. :)