Shuts off itself

I presume when you say it shuts itself off you mean it doesn`t actually come on, It goes to Standby, (Red light). If this is the case, It will probably be the power supply being turned off (Protection mode) by the microprocessor. Have you fitted extension loudspeakers with bad or loose connections? This was a common fault where customers made a bad job of connecting external speakers. I had this once with one set where the customer had a parrot which bit through the cable to the surround sound speakers. Try disconnecting all external connections first, If this doesn`t work, you have fitted speakers and there were taped joints in your wiring, you may have damaged the sound output chip. Other than that, you need an engineer. All modern electronic equipment including TV`s have an inbuilt safety feature to prevent the set from setting fire. It does this by having the computer which controls all the various functions (Including standby) permanently monitor all the voltages within the set. If a voltage is or goes low, possibly indicating a short circuit, the micro detects this and puts the set into standby. Some sets cycle or keep repeating the process of trying to get the set on and then gives up after a certain amount of cycles if the fault does not clear. A good example of this is when there is a very bright screen, the micro could shut the set off thinking the power supply is getting low. Basically what I`m saying is, it`s a workshop job with engineer if non of the fore-mentioned faults exists. Ian

I need some clarification what you mean it just shuts it self off,

First check the power supply inside
if that is good something is heating up causing it to shut down. Thanks

need resolder bad conections in crt yoke conections.