I was having this same problem - power cycling - exactly as described. The lamp turns on and the picture looks good for the 5-10 seconds it is on (this makes me question all the comments I've seen online saying it is a bad lamp that needs replaced). Problems started with green lines on analog channels and erratic behavior that included freezing and shutting off occasionally. Now, it is to the point where I get 5-10 seconds of picture, then it freezes and starts the power cycle 5-6 times, chiming every time it automatically turns on, before finally remaining off. I have removed the back, dusted off fans/components/etc, supplied additional fan for airflow, and made sure the blue switch in the back is down. Still having the same problem!
Ok. I went through the standard warranty process, which means they sent me a replacement bulb saying that was the issue. No luck...same power cycling. Finally they sent a tech out who took a look and said he needed to replace the
digital board. So, 2 weeks later, the part came in and the repairman came back out to install it. Voila, I have a tv again. (This is the same fix the supervisor at the
call center said it needed months ago...before they sent me the lamp)
So...I would recommend having the
tv's digital board checked. Especially if your tv is still under warranty, as
it cost me $0.00 to fix. Chances are, they are still going to start by having you replace the lamp. Good luck!