Tv does not stay on will play for awhile then it goes blank.

that is the backlight that is failing. eventually it will just turn off unless new board is installed

Ur main video board backlight,is dying must be replace to solved this prob.

Do bios update on Computer.Select the product number and search on Website for bios and than try the monitor

tried the cleaner disc you can buy one at
best buy or waltmart

If you can first connect the Fios box via component and that will rectify the issue and still allow HD. HDMI is funny, if there is anykind of communication issues between the TV or the Fios box you see what happens. You might also call Samsung to see if there is ANY firmware/software updated for your TV specifically to fix such an issue with the Fios/Mortorola connection. If there isn't then the issue is the cable box since the TV works ok on HDMI with other devices.

even though lamp came back on and worked for awhile, it was a bad lamp. replaced lamp and set works

Sounds like the CRTs are going into protective blanking due to the vertical output ic needing to be resolderd. Try resoldering the vertical IC that may possibly fix the issue.

sounds like the vertical, more info ctechnicians.com

TV turns on but doesn't stay on goes in and out then blank screen. LED light stays on during the entire time your problem is called hunting you can check power supply of your tv .It common problem in Philips T.V. Thanks