Arfa Daily wrote:

Is the power supply that has blown, the one for the lamp drive circuit ? I'm
assuming that it is as you say the rest of the unit seems to work normally.
You might be lucky, and it be no more than the transistor. I'm not sure how
you determined that the lamp is ok. These are normally a plasma discharge
device, that requires careful start, run and shutdown management, so have
their own power supply, sometimes referred to as the " ballast unit " by
some manufacturers. It runs under the control of the system micro.


Thanks for the tip. I do not know for a fact that the lamp is good, but
I've seen used and new ones and I didn't think this one looked damaged
at all. I am pretty sure the lamp drive is the problem; there are two
hv leads coming from the board with the fried BJT.

Can you point me to some good info on how these lamps work? I have been
googling around unsuccessfully for a while. All I seem to get is
retailers selling lamps.

I agree with you that it would be lucky for me if the transistor was
the only problem, but if I can attempt a repair cheaply enough I'll
give it a go. I'm assuming that the rest of the power supply is okay
because the menus and powerup/powerdown functions seem to work normally
(as far as I can tell without visual feedback).