Replacing pilot lights in Drake L-4B
 

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)

Replacing pilot lights in Drake L-4B
 

I got to agree, if you run a 40 year old vacuum tube amplifier and have
to ask for help on changing a damn pilot lamp.....

Do you even know how to properly run the amp? Can you identify when your
amp is splatteing or non linear.

Heh, maybe its not even the pilot lamp but the fuse !!!



wrote in message
oups.com...
I think I have heard it all now....for sure and certain.. This is the a
clear picture.. definitely an important message here for hams of all
ages.EVERYBODY. make a note of this discussion and remember it...Haney

Replacing pilot lights in Drake L-4B
 

That's about it..... If your amp doesn't have the blue filters, you may
want to find them, too.

Replacing pilot lights in Drake L-4B
 

K3HVG wrote:
That's about it..... If your amp doesn't have the blue filters, you may
want to find them, too.

If you can't find the blue filters, go to your local craft shop, and get
a can of the blue transparent liquid that is used to make wire flower
petals. (you dip a wire "outline" of a petal in this stuff, and it forms
a thin film, like a soap bubble, over the wire.)

The stuff forms an intensly blue/green transparent film that seems to withstand
the heat from the bulb quite nicely.

-Chuck

Replacing pilot lights in Drake L-4B
 

When my lights were workings, the light in the meters was blue.

"K3HVG" wrote in message
...
That's about it..... If your amp doesn't have the blue filters, you may
want to find them, too.

Replacing pilot lights in Drake L-4B
 

I think I have heard it all now....for sure and certain.. This is the a
clear picture.. definitely an important message here for hams of all
ages.EVERYBODY. make a note of this discussion and remember it...Haney

Replacing pilot lights in Drake L-4B
 

The name of your domain is certainly appropriate.

wrote in message
oups.com...
I think I have heard it all now....for sure and certain.. This is the a
clear picture.. definitely an important message here for hams of all
ages.EVERYBODY. make a note of this discussion and remember it...Haney

Replacing pilot lights in Drake L-4B
 

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

--
Remove tilde (~) to reply

Remember the USS Liberty (AGTR-5)
http://ussliberty.org/

Replacing pilot lights in Drake L-4B
 

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

Replacing pilot lights in Drake L-4B
 

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

Replacing pilot lights in Drake L-4B
 

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.

Replacing pilot lights in Drake L-4B
 

"John, N9JG" wrote in message
news:nrlgf.348383$084.317895@attbi_s22...
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)
One stop for good minature bulb references, Chicago Miniature Lamp (now CML)
http://www.chml.com/

Incandescent Lamp Applications (great Tech Notes for bulb selection &
substitutes) - Adobe Acrobat
http://www.chml.com/assets/databookp...Tech_Notes.pdf

An 1850 is a T-3 1/4 Miniature Bayonet Base
ALSO, notice that this bulb only has a 1,5000 hour estimated life
MS CP will give you a "rough" brightness indication for your application

Miniature Incandescent Lamp References (they have LEDs also)
http://www.chml.com/assets/databookpdf/2-53.pdf

w9gb

Replacing pilot lights in Drake L-4B
 

Thanks for the information. I have ordered 10 bulbs (@38¢ each) from Jamco,
and I will soon find out how much of a pain it is to replace the bulbs. If
replacement frequency is too high, I will follow another person's suggestion
and replace the bulb with a 6.3V version. In your estimated life for the
1850, you listed the estimated life as "1,5000" so I'm not sure if you meant
1500 or 15000 hours. 1500 hours seems a bit short. :-)

John, N9JG

"gb" wrote in message
...
One stop for good minature bulb references, Chicago Miniature Lamp (now
CML)
http://www.chml.com/

Incandescent Lamp Applications (great Tech Notes for bulb selection &
substitutes) - Adobe Acrobat
http://www.chml.com/assets/databookp...Tech_Notes.pdf

An 1850 is a T-3 1/4 Miniature Bayonet Base
ALSO, notice that this bulb only has a 1,5000 hour estimated life
MS CP will give you a "rough" brightness indication for your application

Miniature Incandescent Lamp References (they have LEDs also)
http://www.chml.com/assets/databookpdf/2-53.pdf

w9gb

Replacing pilot lights in Drake L-4B
 

"John, N9JG" wrote in message
news:iyMgf.566844$x96.184274@attbi_s72...
Thanks for the information. I have ordered 10 bulbs (@38¢ each) from
Jamco, and I will soon find out how much of a pain it is to replace the
bulbs. If replacement frequency is too high, I will follow another
person's suggestion and replace the bulb with a 6.3V version. In your
estimated life for the 1850, you listed the estimated life as "1,5000" so
I'm not sure if you meant 1500 or 15000 hours. 1500 hours seems a bit
short. :-)

John, N9JG

Sorry John - typo. CML shows it as 1,500 hour estimated life --
yes that is SHORT -- if left on full-time - that is not even a year.
I usually substitute for same or similar brightness
and longest bulb life from CML charts!!

LED is the other choice -- but liight characteristic differences -- do not
match all applications.

Greg
w9gb