TV adjustment help

[dean_martin]

I have a standard Sony 32" tv. Recently, in the lower left portion of the screen it has begun displaying a red/pink patch in the shape of a half moon that goes from the edge of the screen and is approx. 1" by 1". We have moved it recently while rearranging furniture. Is this something that can be repaired by adjustments? If so, does it have to be done professionally? Will it grow like the blob and take over my screen? I have digital cable using the RF/antenna (I think I'm identifying this correctly) connection and dvd w/s-video connection. Any suggestions will be appreciated.

[topspeed]

Is it anywhere near an unshielded speaker or something magnetic? Have you tried to degauss it?

[markw]

Is it anywhere near an unshielded speaker or something magnetic? Have you tried to degauss it?

Good point. Subwoofers are notorious for magnetic fields and yet they tend to have the most powerful magnets of all. Moat people don't even think of that when positioning them. Then they go crazy trying to figure out why the pic is screwy.

...please don't ask how I learned this... ;)

[Kursun]

I have a standard Sony 32" tv. Recently, in the lower left portion of the screen it has begun displaying a red/pink patch in the shape of a half moon that goes from the edge of the screen and is approx. 1" by 1". We have moved it recently while rearranging furniture. Is this something that can be repaired by adjustments? If so, does it have to be done professionally? Will it grow like the blob and take over my screen? I have digital cable using the RF/antenna (I think I'm identifying this correctly) connection and dvd w/s-video connection. Any suggestions will be appreciated.
Most TVs have automatic degauss feature. Switching on and off the TV from the front panel switch (not through the remote control) should do the trick. If not you'll need a degaussing coil. Degaussing a TV screen with such a coil takes less than a minute.

[dean_martin]

Thanks folks - I'll check speaker and subwoofer placement when I get home. I'll also attemp to degauss by clicking on and off from front panel. Lastly, I'll consult the manual.

[woodman]

Thanks folks - I'll check speaker and subwoofer placement when I get home. I'll also attemp to degauss by clicking on and off from front panel. Lastly, I'll consult the manual.

Here's what you must do, Dean ...

By all means, move speakers away from the set before you do anything else. Then, turn the set on (assuming that it's been off for at least 15-20 minutes). If the problem is coming from a magnetic field of a speaker, the built-in "degaussing circuit" should remove the discoloration. However, this circuit only functions from a "cold start". After the set has been "on" for a few minutes, the circuit becomes inoperative until the set has been turned "off" and left off for at least 15-20 minutes. This is due to the use of a thermistor in the degauss circuit. It's a special kind of resistor that changes it's resistance with heat. When it's "cold", the resistance (to current flow) is only a few ohms. As it heats up (due to that flow of current) the resistance increases very rapidly to the point where it keeps all current from flowing through it at all.

If this fails to cure the problem, degaussing the screen with an external degauss coil should be tried, but this must be performed correctly in order to be effective. If it comes to that, let me know and I'll explain just how it should be done.

[kfalls]

Forget the degaussing and speaker moving, this is a pretty common problem with Sony TVs, one I suffer from myself. Most resolutions I've seen require a Sony service technician placing purity magnets on the picture tube. Mine started as a small spot in the lower left corner which gradually got larger then spread to the right side of the screen. It appears as shades of red, blue and green most noticeable on white or light backgrounds. Of course it happened after the warranty ran out. I have the 36XBR250 and it's really agrivating to pay big bucks and lug a 240lb TV upstairs then have it go out of alignment. After my experience and seeing the complaints of many others, I won't buy Sony again.

[skeptic]

When I had my Teledyne AR9s near one of my Sony KV2781R sets in my old house, I had the same problem. I had to drag the speakers halfway across the room before the color fringing in the corner disappeared and I was convinced there was nothing wrong with the picture tube. I own FOUR 36XBR250s which have been in use for over 4 years and have never had any trouble with any of them. The AR9s are about the same distance from the TV set as before but it appears to be much better shielded. The AR9s have 2 12" side firing woofers each and are unshielded. They are no more than a few feet from the tube.

I don't know if there are adjustment magnets on the yoke of Trinitron tubes the way conventional picture tubes have but if there are, one of them may have gotten knocked lose during the move. Woodman would probably be able to answer that. He's always right on the money on just about anything to do with electronics.