Bill KC0IZI wrote:

Does anyone know the specs for a replacement of the pilot lamps
behind the main tuning dial?

The original Yaesu part number was: BQ154-33811A.
One source said is was 12V. 100ma. Is this correct?
Both of mine burned out as I flicked the `light' switch
off and on.
The lamps are those `grain of wheat' types . . .
Any help or suggestions on replacement or a source would be
appreciated.

Bill, KC0IZI

Hi Bill,

Hobby shops are good places to shop for grain of wheat lamps (typically
available in 6V and 12V types). Two issues with using 12V lamps:
a) your AC power supply or automotive charging system supplies 13.8V but the
lamp is rated for only 12V... running current will be high (lifetime will be
significantly shortened).
b) the inrush current (often several times the running current) is quite
high, even if you regulate the voltage. The lifetime is again shortened.
You can use a *current* regulator, set to some value less than the lamp's
current at its design voltage. For currents less than 100mA, the LM317L
would be an excellent choice and is super easy to implement.

Colin (K7FM) suggested replacing the incandescent lamps with LEDs but
mentioned the dispersion angle would be very narrow (creating a spot of
light). A friend who runs a service shop for commercial sound gear tipped
me off... grind/file/sand the lens of the LED. The LED will now have a very
wide dispersion angle.

73,
Bryan WA7PRC

Bryan wrote:


Hobby shops are good places to shop for grain of wheat lamps (typically
available in 6V and 12V types). Two issues with using 12V lamps:
a) your AC power supply or automotive charging system supplies 13.8V but the
lamp is rated for only 12V... running current will be high (lifetime will be

Mouser has a pretty good assortment, and unlike the hobby shop, you can find
the actual specs for voltage, CP, and hours life.

-Chuck

Chuck Harris wrote:
Bryan wrote:


Hobby shops are good places to shop for grain of wheat lamps (typically
available in 6V and 12V types). Two issues with using 12V lamps:
a) your AC power supply or automotive charging system supplies 13.8V but
the
lamp is rated for only 12V... running current will be high (lifetime
will be

Mouser has a pretty good assortment, and unlike the hobby shop, you can
find
the actual specs for voltage, CP, and hours life.

-Chuck

Gee... the last batch of 10 ($10 US/pkg) I bought from the local hobby
emporium were marked:

Mfr: Miniatronics Corp
PN: 18-028-10
Voltage: 14V
Current: 80mA
Dia: 5.5mm
Average Life: 10,000 hours
Website: http://www.miniatronics.com/

The light output wasn't listed but for the price/availability vs the
non-critical application, it's not much of a gamble. They have lotsa other
stuff as well, and have a dealer locator on their website. Again, if using
incandescent lamps, limiting the inrush current will maximize the life of
the lamp. I used an LM317L + one resistor to do that.

Bryan

Bryan wrote:
Chuck Harris wrote:
Bryan wrote:

Hobby shops are good places to shop for grain of wheat lamps (typically
available in 6V and 12V types). Two issues with using 12V lamps:
a) your AC power supply or automotive charging system supplies 13.8V but
the
lamp is rated for only 12V... running current will be high (lifetime
will be
Mouser has a pretty good assortment, and unlike the hobby shop, you can
find
the actual specs for voltage, CP, and hours life.

-Chuck

Gee... the last batch of 10 ($10 US/pkg) I bought from the local hobby
emporium were marked:

Mfr: Miniatronics Corp
PN: 18-028-10
Voltage: 14V
Current: 80mA
Dia: 5.5mm
Average Life: 10,000 hours
Website: http://www.miniatronics.com/

That's great! I am more used to them being marked something "useful"
like: locomotive lamp, or street lamp, 12V...

Mouser sells that same lamp (by Chicago Miniature Lamps) for $0.43 each
in a pack of 10. They have no minimum order.

-Chuck

Chuck Harris wrote
Bryan wrote:
Chuck Harris wrote:
Bryan wrote:

Hobby shops are good places to shop for grain of wheat lamps
(typically
available in 6V and 12V types). Two issues with using 12V lamps:
a) your AC power supply or automotive charging system supplies 13.8V
but
the
lamp is rated for only 12V... running current will be high (lifetime
will be
Mouser has a pretty good assortment, and unlike the hobby shop, you can
find
the actual specs for voltage, CP, and hours life.

-Chuck

Gee... the last batch of 10 ($10 US/pkg) I bought from the local hobby
emporium were marked:

Mfr: Miniatronics Corp
PN: 18-028-10
Voltage: 14V
Current: 80mA
Dia: 5.5mm
Average Life: 10,000 hours
Website: http://www.miniatronics.com/

That's great! I am more used to them being marked something "useful"
like: locomotive lamp, or street lamp, 12V...

Mouser sells that same lamp (by Chicago Miniature Lamps) for $0.43 each
in a pack of 10. They have no minimum order.

-Chuck

Cool. Because of pricing, I've found myself buying from Mouser (and even
Allied) more often and Digi-Key less often. For dial backlights, I think
I'll give the white LED another try, the next time around. I want to try a
friend's suggestion to file/grind off the lens in order to increase the
dispersion angle.
Bryan WA7PRC

Bryan wrote:
Chuck Harris wrote
....
Mouser sells that same lamp (by Chicago Miniature Lamps) for $0.43 each
in a pack of 10. They have no minimum order.

-Chuck

Cool. Because of pricing, I've found myself buying from Mouser (and even
Allied) more often and Digi-Key less often. For dial backlights, I think
I'll give the white LED another try, the next time around. I want to try a
friend's suggestion to file/grind off the lens in order to increase the
dispersion angle.
Bryan WA7PRC


I've done that as well. In some cases where I can, I will string 3 or 4 LED's
in series and use them to light up the dial.

White LED's are funny devices. As I understand things, they are actually
blue LED's with a phosphorescent component added to the plastic of the package.
The phosphor is what makes them radiate white. I have a suspicion that filing
them may damage the color. Old fashioned GaAs LED's dispersion can readily
be improved by filing the end of the lens.

-Chuck

Chuck Harris wrote:
White LED's are funny devices. As I understand things, they are actually
blue LED's with a phosphorescent component added to the plastic of the package.
The phosphor is what makes them radiate white. I have a suspicion that filing
them may damage the color. Old fashioned GaAs LED's dispersion can readily
be improved by filing the end of the lens.

Yes, you can't file the whole lens off, but you CAN rough it up with a bit
of sandpaper to create a diffusing surface. You don't want to take any more
material off than you have to.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

wide angle LEDs:

Check out:

http://ledsupply.com/

This is a white wide angle (70 degree) LED

http://ledsupply.com/l1-0-w5th70-1.php

Also of interest - is

http://ledsupply.com/l1-0-ww5th50-1.php

which is a warm white 50degree - VERY bright- and mimics incandescent
pretty well - esp. if you "throttle them back" (i. e. run them 10-15ma
istead of rated 20ma).

Of course - they still aren't "global" like true incandescents - but
with the low current drain - you can afford to use several for the same
power budget... and aim them along a path, etc.

best regards
--
randy guttery

A Tender Tale - a page dedicated to those Ships and Crews
so vital to the United States Silent Service:
http://tendertale.com