If you’ve not done so, look into replacing/getting replaced the electrolytic capacitors in the TV. They are one of the only parts that truly suffers from aging. By the sound of it, some of yours are on their last legs. If you replace them before they go completely, you can limit the damage. A failed cap can often cause damage to other components.

The caps will generally have their value and tolerances printed on them. They are ¢ each, so it’s fairly cheap, parts wise.