My 46" lcd had that problem...replaced two of the capacitors and problem solved... (only two looked bad; others looked fine)
Now I have a new problem. My speaker volume is way too low, and I'm not sure why.
And for the record my TV is also only 14 months old. I'm not real happy with samsung right now.
My 14 month old LN52A750R1F has the same on/off problem as others. So I have spent the last couple days researching this issue. Since Samsung isn't interested in fixing their problem, and they won't repair it under warranty, I decide to take a peek at the capacitors on my power module. The board is a BN44-00201A SIP528A Rev 3
The caps look normal, not swollen like I was expecting. I searched and found a new board from discount TV Parts for around $90 shipped. It should arrive here in a couple of days. I will swap the complete board out instead of soldering in new caps.
I'm worried this won't fix the problem, since I read a post where a guy swapped in a new board and it still cycled on/off.
If mine still is not working, I will swap out another board or two until it gets fixed. Then I am going to change jobs to a TV technician:-)
I'm really disappointed in Samsung. I will never buy from them again, and will spread the word. I have filed complaints where ever possible.