Hi. I'm Steve. I'm sorry to hear about your TV. I will try my best to give you a precise and accurate answer.
I'm not over-familiar with Sanyo LCDs but I will tell you that the most likely problem is the loss of one of the CCFL lamps that provide the backlight. Typically there is a balancer circuit that works with the two inverters. When it detects a mismatch in load (when a lamp fails), it will signal the power supply to shut down the inverters.
You say that the screen is lit for a second or two...in a darkened room, see if you can determine where the failed lamp is located around the perimeter of the screen.
Then, you have to decide whether or not to try and change out the lamp. This is the domain of the very brave but it can be done and the lamps are readily available: http://www.ccflwarehouse.com/
It is also possible that you will destroy your panel. Personally, I have never done one of these swaps.
I'll be here if you need more help. I want you to be 100% satisfied with my answer.
Please bookmark my web page at www.stevetheguru.com so that you can contact me with your future electronic questions.
Thanks very much.
I did receive payment. Thanks very much.
As I indicated previously, I'm not familiar with the Sanyo unit you have there but a typical length is 2" (50mm). So divide the perimeter of the panel by 2" and that will be in the ballpark.
Again, the way to see which one is out, is to dim the room and keep turning the TV on and off and try to see where around the edge has a dark space. That's the bad lamp.
Get the size and go to www.ccflwholesale.com