John, N9JG wrote:
Thanks for your helpful suggestions. Yes, it looks like the bulbs are
socketed (aimed towards the front panel), but it wasn't clear to me if I had
to remove the front panel in order to get maneuvering room. As others have
suggested, it should be a "lark" to replace the bulbs unless the glass
breaks off with the bayonet base still in the socket. Then it might be time
for some strong language.

In the (unlikely?) event that the glass breaks, you can use an
appropriately-sized bit of rubber (the eraser on the end of a pencil,
or one of the slip-over erasers) as a tool for removal: just push it
down into the metal base as far as you can, then twist. I've done this
more than a few times with old pilot lamps.

--
Don't join the book burners. Don't think you are going to conceal
faults by concealing evidence that they ever existed.
- Dwight D. Eisenhower