I have the same television LN52A650A1F. I too have the same problem with my tv. I tried the firmware update and still the television won't turn on. I found that the power board is what seems to be failing. The tv gets to hot and the capacitors swell and even explode. I am past my warranty so I took a look around in the back to see what was going on and was able to see that the capacitors were in fact pretty swollen. I am currently waiting for a new power board in the mail and will let you know what the out come is.