This sound like the power supply board is failing. The electrolytic capacitors on the board may need to be replaced.
IF YOU KNOW HOW TO WORK WITH ELECTRONICS REPAIR(soldering ) or have a friend with knowledge/skill you can fix it.
>Unplug the set.
>Remove the back cover.
>look at the
capacitors on the power supply board. If the
top of any of them are
bulging up that is the problem.
>You will have to
replace ALL the electrolytic capacitors except for the large one.
> Use ones with the
same farad rating
> Use ones with the
same or higher voltage rating
> Use
high temperature rating
> Install one at a time to prevent mixup and keep the polarity correct.
> Leave a space between the PC board and the bottom of the capacitors for expansion. They heat up.
THIS IS AN INDUSTRY WIDE PROBLEM AFFECTING MANY COMPANIES AND PRODUCTS.
One source for some good capacitors is NTE. Try nteinc.com for a local outlet.
You can also search for other sources. Some companies even sell pre package kits of capacitors.
Total price of parts should be