The message
from shorepot15 contains these words:

The light in the microwave has failed - I assumed it would be a matter
of replacing the bulb as you do with a fridge or an oven. I undid a
couple of screws and a small panel came off but there was no bulb
there and the manual doesn't mention it at all. What's going on? Is it
not user-replaceable?

I have an old Panasonic that I inherited when my father died in 1995.
That later went dark and after some years I eventually took the casing
off to see what sort of bulb I needed to get. Turned out I didn't need a
new bulb as the original was unscathed, just loose. Seemed it was not
the first time that the bulb had come loose as someone had tried to
restrain it with selotape. I just twisted it tight again and so far at
least it hasn't come loose again.

--
Roger Chapman