Just an update. The TV quit working within a day of my initially getting it to work using the heat gun approach. So this time I heated it up again at 900 degrees F for over a minute holding the heat gun much closer as in about .5 inch of the heatsink and then right after that put a 10 lb weight on top of the heatsink (something that I had not done initially) and let it sit for a while until it cooled down and then removed the weight and powered it up. It has been working fine now for over a week.
Also installed two small fans for cooling. So far so good. I think applying the weight after the heating up was important.
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