John, N9JG wrote:
I am planning to order meter illumination pilot lights for my Drake L-4B
from Play Things Of Past http://www.oldradioparts.com/. The pilot lights are
type 1850, 5V @90 ma, bayonet. I would like to know how easy/difficult it is
to replace these bulbs. I am hoping that all I need to do is to remove the
amplifier top cover. The instruction manual does not mention replacement of
these pilot lights. Maybe they did not anticipate that the amplifier would
still be in use after 30 years.

John, N9JG

(remove ".XremoveY" from above address)


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

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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

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

This sounds like a very useful technique, and one worth keeping in mind.
Thanks for pointing it out.
-- John, N9JG

"Mike Andrews" wrote in message
...
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.