Hello, I want to share the repair you make with this tv. The TV turns on and looks and listens well but after a few seconds it turns off. Then perform verification and correction of welding and thinner cleaning. The TV remained the same. check output voltages and these were fine B + 134v on STANDBY and 130v ON and 7.5v of STANDBY in 7.4v this is correct. then investigate and according to suggestions on the web they said that the transistor Q751 C3198 as a 5v regulator used to be damaged by leaking so replace it like the Q752 C3198 as a 3.3v regulator with the C1815. But the TV continued with the fault. I continued to verify the correct polarization of the jungle and it was fine on pins 54, 56 and 61 with 3.3v. I decided to check the stage of x-ray protection on pin 8 of the PROT IN jungle and it was on 9v on and when it was turned off it fell to less than 2v. You found the line where this signal came from. And I started checking components at that stage. I didn't find faulty components apparently but according to this link http://13norte.blogspot.com/2011/06/21v1-l-enciende-normal-pero-luego-se.html the zener diode D603 27v is leaking by temperature so replace it But the problem continued. Seeing that the voltage on the PROT IN Pin was very high when the TV was on I made a bridge between collector and transmitter of Q603 to see the reaction, the TV did not turn off and the voltage in the PROT IN ping was about 4v to 6v. Which made me suspect that transistor I changed it but the problem continued. Then I followed the collector line of Q603 reaching a diode and resistors Check all resistors and they were fine. Verify diode D601 DX0475CE and average well in direct but in average approximately 1800 on the diode scale So I took them out to confirm and that diode was damaged, it was leaking, I replaced it and the TV was working properly. The diode does not bring numbers only a yellow band so look for an identical one in another panasonic chassis. But it can be used whatever rectifier is like 1n4001 to 1n4004 or a 1n4148. Here the link to download the diagram. https://elektrotanya.com/sharp_ga1_chassis_14lk14.pdf/download.html I hope you find the information useful. Success in your repairs.