Hello,
It is likely on the video board.
At today's price point, it is often less expensive to replace with a more modern television that can be hung on the wall, and does not take up so much valuable floor space.
Good luck with your repair.
Certainly you can have it fixed, consider if you will the high cost for replacement parts. Generally, the fix is more expensive that getting a whole new TV. The Plasma TVs are now a dinosaur and new 4K Ultra TV's are in. The cost for a less expensive Walmart TV is $300. Consider the cost involved in fixing an old TV.
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