I have a Philips 30PF9946D/37 no picture

what you have is a bad inverter transformer on the inverter board. I nashed my teeth on this problem for a long time because no diagram is avail. Here's the fix for you:

Remove the invertor board. Take an Ohm meter and measure the outer 4 legs of each transformer. Between pins 1 and 4 (side with the white dot near leg 1) you should read .3 ohms. This side is usually good. Between pins 5 and 8 you should read approx 1.8 to 1.9Kohms. ANYTHING above that is a defective transformer. I'm sorry I do not have the part number for this, I've just been using an old board from a set with a cracked panel. If I can find a part number I will try to post. You can try Encompass parts on the web, they may be able to supply part number and transformer with location number.

Rick
W2ICA

I had the same problem and after testing all the legs on the transformers I accidently created a groun dwith one of the lead from my multimeter. I procede to test the the ground on the transformer board and to my surprise one was missing. I created a ground by grounding the ground from the transformer board the the chassis of the tv. This was 3 or 4 mths ago and it still is kicking. This was my problem.