I checked the Sams Photofact online index and nothing turns up on that model number. I think a service manual is in order for this set. Try
www.tritronics.com and see if one is available. The only other thing I can suggest is get a service manual from Philips and check all the power supply voltages. It could be possible that the B+ is high and triggering a shutdown circuit. Many of these newer TV's have so much "fault detection" circuitry that the older sets did not have. On the older sets, whatever was wrong just shorted and smoked something, making it real easy to find the trouble.