If this unit is only a few months old, then it may still be under warranty. If not, then you could start by looking at the IHVT high-voltage circuit. More than likely your horizontal transistor is faulty and needs to be replaced. If you try to replace it then remove the old one first and keep it with you when you buy a new transistor, so you'll know which one to get (make sure the numbers match).
Of course, if you don't know how to solder electronic components then take it to a service center (they'll just tell you the same thing I did, but they'll charge you for doing it).
J. Lee, Palmetto Electronics, April 2005
