Dewitt wrote:
It's getting power and the transformer is vibrating a bit, but there
is nothing coming from the bulb. I suspect it's likely the bulb but
don't have a spare to try. Any ideas on how to diagnose where it's
actually the bulb or possibly the transformer? Guess I could take a
meter to the socket and look for power there, but I don't know what
voltage to look for and really wouldn't want to accidentally short it
out.


I agree with the other poster; buy a new bulb and see if it works.
When you take out the old bulb, look for any obvious signs of a
problem, such as loose bits, broken connections in the bulb, etc.

If you really want to troubleshoot it with a multimeter, the unit or
the transformer itself should have its output voltage marked on it
somewhere. Did it come with a schematic and a rundown of its
electrical requirements and outputs? If so, check that.

J. Del Col