Television and Home Theater

This TV supposedly has or based on the Hitachi chassis DP15, which is in Hitachi models 43FDX10B, 43FDX11B, 53UDX10B and 61UDX10B. I searched all them models and didn't find any no video or sound problems.

When turned on you hear reply click and power light stays on and TV stays on as if it was operating normally.  But theirs no picture or sound except a pop from speakers when turned on. On the circuit boards all green and red Led's are steady lit, no pulsing or dimming. Theirs no high voltage static charge sound to the CRT when turned on.

So i have this model and it will power on then after 5-7secs., power right back off. I look in this forum for some info and find that i can run a diagnostic on it. When i do this, it comes back with the error code 21. From what i read on here, this means "X-Ray Protect Circuit".

The thing is, i can't find anything else about it other than the error code meaning. How can i repair this problem?? Where do i start? What do i look for once inside the set its self???

Please help! Any help at all will be greatly appreciated...

hello have a rca scenium hd50lpw175yx12 and it has green tint to it and screen flickers anyone got any suggestions thanks