HDTV Forum

More than likely with this symptom you have a direct view CRT from 13-40". CRTs are susceptible to magnetic fields including the earths magnetic field and more often than not you have this symptom due to a speaker that is nearby. First step is to turn the TV off and allow it to cool down for 2 hours and turn it back on. This will turn on the degaussing circuit which will try to neutralize any DC magnetic fields on the CRT and hopefully your problem. If not and this symptom appeared from moving a speaker then you must put the speaker further away from the display or purchase a speaker that is magnetically shielded specifically for this application. Most center channel speakers are shielded for this reason.

Sometimes the internal degausser does not have enough strength to remove heavy magnetic fields and will require service to manually degauss the CRT.

If this splotch is intermittent and appears to be associated with bright images in that area check doming.

We tried to lower the contrast but the blotch is still there. You said something about having the internal
degausser manually degaussed, does this mean a service call from a television tech. I don't know if they will come to your house anymore. The television is too heavy to move.

they still come out... tell them your problem and that you would like to have it degaussed. This is based on you just one day having this blotch...

The shadow mask can also separate from the screen and that too will cause this problem but is typically related to dropping or jarring the product. If this is the case that means new CRT and that means buy a new TV - the repair is that expensive.