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.

"Roger D Johnson" wrote in message
...
I replaced the ones in my L-7 with common type 47's. The 6.3 volt
bulbs give adequate illumination and should last forever on 5 volts.
The 5 volt bulbs are kind of rare.
On the L-7 all you have to do is remove the cover. The bulbs are in
sockets right at the meters. I presune the L-4 is the same.

73, Roger