I guess with two handy ballasts and one probably "rescued" since when they are working they find no need to refurbish them in my experience.. I would rule out the power supply out put with a multimeter just in case, but that is highly unlikely to be the cause.
Now the lamps you have, are those OEM Philips? As you might have noticed Samsung uses Philips lamps.. the other just do not last as long as they should. If they are Philips, how long have they been working?
My reasoning is that even though both lamps you have are "saying" your ballast is bad, I have been there before and a new lamp has been the solution..
I hope I can help!