First of all thank you for contacting Fixya.com regarding your TV problem.
You have mentioned that you can hear a high pitch near the thermistor area and the TV won't power up. I've saw also in another link that you already replaced the thermistor but the symptoms still persist. You stated that the thermister heats up, that is normal and not an issue in this kind of symptoms. You can power up the unit even without the thermistor in the board and check if the high pitch will gone or not. But I've suspected that the symptoms will remain the same because the pitch came from the chopper transformer.
I've encountered this kind of symptoms not only on panasonic CRT TV's but almost in all brands. And the major caused of fault is the faulty electrolytic capacitor in the Voltage regulator IC. Your unit used STRF6524
(mounted on the aluminum heat sink) as voltage regulator IC and it has an electrolytic capacitor on its circuitry. I would advice you to replaced it to resolve the issue. The largest electrolytic capacitor is not the suspect here (don't replaced it).
Also check for bad solder joints around the regulator IC. Cracked, cold, dried solder can produced that kind of symptoms. It is hard to spot, you must used magnifying glass and work in the brightest area or much better to re-solder the suspected bad solder joints.
I have various of Panasonic schematic diagram but most of them is a LCD and Plasma TV. I don't have this model no. but please check the chassis no. of your unit and I will try again to find it on my supplier to give it to you for free as much as possible because I've saw it HERE
but I don't think the price is reasonable.
Please let me know if you need further assistance.
Again, thank you and have a nice day!