Hello, and sorry you're having problems. We are now connected on this website- which saves you money over having a Tech come to your home, and in many cases we can fix the problem you're having. In other cases, these things do require additional parts to fix. But I can help you with that as well.
When a Plasma panel (screen) is cracked- this is a fatal failure within the TV. The screen is powered by the Sustain and Buffers/Drivers, and a cracked screen will take out these boards when it cracks. So at the very least we have two boards that need to be replaced, at an average cost of $300-$350 parts and labor at a shop.
Now for the bad news, the display panel (Plasma screen) would need to be replaced to fix this. The ENTIRE screen is one piece (meaning the under layer that has the plasma inside, and the outside glass). The cost of a Plasma display panel is well over $1,000- and that is when/if you can find one available. The entire TV needs to be rebuilt from the inside out to replace the panel.
So to repair this set would cost you on average $1,500- which is simply not cost effective on this- or any TV for that matter. Reason being is a brand new 50" 4K LED Smart TV by about any brand out there- will cost you this, or less to purchase and have a brand new set. For example, the entry level 4K LG Smart TV at the link below is only $700 at Best Buy:
I'm sorry for the bad news here, and with there were an economical fix, but your 50" Panasonic would be better off replaced, versus being repaired from a cost standpoint.
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