Solved! Repaired or so i thought..

[maustk79]

We just had the motherboard replaced in our Toshiba TV model # 46SL417U, It turned on for approx. 10-15 min. and shut itself off, tried unplugging it anf it clicked and green light came on and shut off & now it will not power on, what might be causing this?

 

[americanaudiophile]

Given the age of the TV I suspect that the mainboard was not new original stock but either removed from a set or a maybe a remanufactured board. I don't see that board online for sale so I suspect it may have been salvaged. Hope that the place that did the repair will take care of it for you.
A set that old isn't usually a good candidate for anything other than a very cheap repair.
I just replaced a Fujitsu 50" plasma TV that was 19 years old but it still worked fine. I don't think you can expect that of new TVs.