First thing to do is to change out the 6.3A fuse. If it powers up like nothing happened then your problem is with the degausser demanding too much power. The thing about where to buy it.... i do know that most can still be bought at places like octopart, etc.
I am sorry for my previous post... it can be considered a positor... but it is more of a thermistor in circuit with the degausser. When the degausser starts taking a number of current, this thermistor stops conducting and stops the degausser. The value is too low with these so the degausser takes up too much current before shutting the relay off.
The best would be to give me your model number.
This is the part in some panasonic crt's.
But mind you that the 1R5 (1.5 ohm) is too small and i usally install a higer value that i strip from any other type of tv.Usually a 3r0 (3 ohms) will do the job just fine.
If u give me your model number i can tell you position on board.
If you dont know much of soldering and all, bring only the main board to a tv repair shop and ask them to change the degausser thermistor. The part itself is no more than 10-20$ and can be found on almost any CRT tv from the 90s 2000s. Just be sure they swap a higher value.
Be careful as electricity in these tv's never goes away...unless you discharge the crt. This is dangerous and potentially harmful. Be warned. No repairshop should charge more than 100$ at the shop and 140$ at home for this and the TV will last for at least 15 more years. These panasonics have VERY little problems so i recommend repairing it. While you are there adjust your Screen on the flyback so you can watch your tv with the brightness at 31