> Gentlemen, I installed six annunciator lights from two old
> autopilot systems in my panel. Now that I am testing the wiring,
> I find that 10 of the 12 interior bulbs are burned out.

You could replace all those bulbs with similarly reliable new bulbs,
or you could take this opportunity to replace all twelve with LEDs
that will probably never need replacement. Even the cheapest LEDs
out of Hong Kong will be more reliable than the most expensive
incandescent bulbs. Expect to use about one tenth the current,
and be able to choose the color as well. For 12V systems, LEDs
with internal ballast resistors are common. For 28V systems,
you'll probably have to attach your own ballast resistors - which
is an easy soldering job.

Let me know if you want to switch to LEDs and need more help
to figure out how to do so.

-bob