I am yet another customer experiencing the on/off cycling problem on my Samsung LCD TV. My model is a LN46A650, which was purchased on NewEgg.com 08/17/2008. The problem first appeared on 04/15/2009, so I am lucky enough to still be under warranty.
The first time it happened was in the morning after it had been off all night. After turning on the power, the TV cycled on and off automatically about 4-6 times before it stayed on (at which point, it stayed on without incident the rest of the day).
The next morning the same thing happened, though this time it cycled on/off about 8-10 times before staying on (again, it was fine then the rest of the day). However, at this point I realized there must be a problem with the TV, so I googled and discovered this thread.
I located and downloaded the Firmware update for my model and applied it as directed through the wiselink usb port. After applying the firmware update, I turned the TV off and then back on to see if it fixed the problem. It came back on without issue, so I assumed the problem resolved.
However, upon turning the TV on this morning - it went back into the same on/off reboot cycle and did so about 16-20 times before it would stay on. After realizing the firmware did not fix this issue and that the problem was getting worse - I called Samsung Customer Service to schedule a service call.
I am now waiting to hear back from a technician as to when they can come over to look at the TV. I was told someone should get back to me within 24 to 48 hours, so I am hoping this isn't going to take a month or longer to be resolved as other people have reported.
Because this exact problem appears to be a chronic issue for so many other people (and between varied models), I must say that my consumer confidence in Samsung is severely shaken. It seems quite apparent that a batch of their LCD TV's shipped with faulty or bad hardware. Because of this and the product price range we're talking about, there should be an automatic warranty extension in effect for all consumers having this issue with their TV. As mentioned above, I'm lucky enough to still be under warranty - but had this happened a month or two past that point, I would have been pretty upset if they refused to fix it.