Hi Janet,
Carefully remove the back, it's probably held on by screws around the edge. It will be a heavy set so make sure it's on something firm, a stand or bench, etc. Then switch on while looking in the back and see where it's arcing over. Be careful of high voltage, you'll be OK if you look but don't touch. It's probably either where the thick wire takes the high voltage into the side of the glass picture tube or at the base of the tube (the narrow tubular part at the rear of the glass where the wires and socket connect).
It could also be on the main circuit board, somewhere near where the thick lead from the tube side starts.
There is very high voltage here, up to 30,000 volts in a big screen set like yours and if the insulation isn't perfect it can arc over. Be careful not to knock the glass.
When you can see what's happening, switch off,replace the back with a couple of screws to prevent knocking anything and tell me what you've found. I'll then suggest what to do next. Don't continue to use it until fixed, it might cause damage. Hopefully the insulation can be easilly fixed.
Don Black.
: We just bought a used Mitsubishi TV - 35 inch while transporting it home it did fall face down on a soft rug. We hooked it up and color is beautiful but every few minutes it makes a static sound and the picture makes static type lines. This is very hard to describe - we don't have alot of bucks - does anyone have an idea of what we could possibly do to fix. please let me know. Xrealtorx@aol.com Thanks