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<DIV><FONT face="Lucida Fax">All -</FONT></DIV>
<DIV><FONT face="Lucida Fax"></FONT> </DIV>
<DIV><FONT face="Lucida Fax">The LEDs I've ordered </FONT><FONT
face="Lucida Fax">are, indeed, AC/DC types and are supposed to draw about 20
mils. See <A
href="http://cointaker.com/searchquick-submit.sc?keywords=g44f">http://cointaker.com/searchquick-submit.sc?keywords=g44f</A> </FONT><FONT
face="Lucida Fax">for an example.</FONT></DIV>
<DIV><FONT face="Lucida Fax"></FONT> </DIV>
<DIV><FONT face="Lucida Fax">Bob AG5X</FONT></DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=k4oah@mindspring.com href="mailto:k4oah@mindspring.com">Garey
Barrell</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=boatanchors@puck.nether.net
href="mailto:boatanchors@puck.nether.net">boatanchors@puck.nether.net</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Saturday, February 05, 2011 10:03
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [Boatanchors] #44/47 Bulb
replacement with LEDs</DIV>
<DIV><BR></DIV>Al -<BR><BR>Apparently the filament will carry the full 150 mA
through that tapped <BR>section, rather than the ~75 mA it sees with a
parallel #47. I suppose <BR>the higher failure rate of this filament
section in radios run with <BR>blown bulbs could be coincidental, but I've
replaced a LOT of 34W4 and <BR>35Z5 rectifiers in my life, and most of them
had a blown bulb and Pin <BR>4-6 (or 2-3) open.<BR><BR>It makes sense that the
entire filament would be able to handle 150 mA, <BR>but without a bulb that
filament section is dissipating a little over 1W <BR>and with a bulb a little
less than 1/2W, not counting the DC current <BR>which also goes through the
filament. So without a bulb that section <BR>would be the most likely to
fail. Of course these were both very <BR>inexpensive tubes, and a bulb
or even a resistor cost money in a VERY <BR>price competitive market.!
:-)<BR><BR>As for the original question, if the LED was of the AC/DC types, it
<BR>should work fine. The voltage across the tap is 7.5 V with NO
parallel <BR>load and as long as the LED will handle that voltage it should be
ok.<BR><BR>73, Garey - K4OAH<BR>Glen Allen, VA<BR><BR>Drake 2-B, 2-C/2-NT,
4-A, 4-B, C-Line<BR>and TR-4/C Service Supplement CDs<BR><<A
href="http://www.k4oah.com">www.k4oah.com</A>><BR><BR><BR>Al Parker
wrote:<BR>> Hi folks,<BR>> In the AA5 or 35W4
application, aren't we missing one of the <BR>> purposes of the lamp?
It provides a load to balance out the voltage <BR>> wanted across the tube
filament. An LED lamp is much lower a load, in <BR>> the neighborhood
of 10%, so it's not going to serve that purpose.<BR>> 73,<BR>><BR>>
Al, W8UT<BR>> <A
href="http://www.boatanchors.org">www.boatanchors.org</A><BR>> <A
href="http://www.hammarlund.info">www.hammarlund.info</A><BR>><BR>>
"There is nothing -- absolutely nothing -- half so much<BR>> worth doing as
simply messing about in boats"<BR>> Ratty, to Mole<BR>><BR>> On
2/5/2011 10:07 AM, Michael A. Bittner wrote:<BR>>> Chuck, Thanks for the
info and data sheet on the 35W4. Looks like it's<BR>>> OK to use the
35W4 in a series string without harm as in my Knight Ocean<BR>>> Hopper
and according to the alternate diagram on the data sheet.<BR>>> This
still leaves us with the question of how one of these #47 bulb LED<BR>>>
substitutes would work in an AA5 radio. After all, the D in LED
stands<BR>>> for diode.
W6MAB<BR>>><BR>>> ----- Original Message
-----<BR>>> *From:* Chuck <<A
href="mailto:wcmoore@verizon.net">mailto:wcmoore@verizon.net</A>><BR>>>
*To:* <A href="mailto:infomet@embarqmail.com">infomet@embarqmail.com</A>
<<A
href="mailto:infomet@embarqmail.com">mailto:infomet@embarqmail.com</A>><BR>>>
*Cc:* <A
href="mailto:boatanchors@puck.nether.net">boatanchors@puck.nether.net</A>
<BR>>> <<A
href="mailto:boatanchors@puck.nether.net">mailto:boatanchors@puck.nether.net</A>><BR>>>
*Sent:* Friday, February 04, 2011 9:45 PM<BR>>>
*Subject:* [Boatanchors] #44/47 Buld replacement with
LEDs<BR>>><BR>>> The 35W4 is a bit of a
strange bird. The filament is tapped but<BR>>>
rather than<BR>>> being tapped at the center
like the venerable 12AU7 and similar<BR>>>
valves the<BR>>> 35W4 is offset so that there
are different drops across each<BR>>> filament
section.<BR>>> From Pin 3-4 with a #47
Lamp the filament drop is 32 Volts. From<BR>>>
Pin 4 - 6<BR>>> the nominal drop is 5.5
volts.<BR>>> For more info see the datasheet at
the follwoing URL:<BR>>> <A
href="http://www.r-type.org/pdfs/35w4.pdf">http://www.r-type.org/pdfs/35w4.pdf</A><BR>>>
> Great question......thanks, Mike!<BR>>> > 73....Walter - K5EST -
Missouri<BR>>> ><BR>>> ><BR>>> > On Thu, Feb 3,
2011 at 7:39 PM, Michael A. Bittner wrote:<BR>>> >> How would
these work in an AA5 radio where the #47 bulb is often<BR>>> >>
connected<BR>>> >> across one half of the rectifier heater?
Rectifiers are<BR>>> typically 35Z5
or<BR>>> >> 35W4 with center-tapped heater. Mike W6MAB<BR>>>
><BR>>> >
_______________________________________________<BR>>> > Boatanchors
mailing list<BR>>> > <A
href="mailto:Boatanchors@puck.nether.net">Boatanchors@puck.nether.net</A><BR>>>
> <A
href="https://puck.nether.net/mailman/listinfo/boatanchors">https://puck.nether.net/mailman/listinfo/boatanchors</A><BR>>>
><BR>>><BR>>><BR>>><BR>>>
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href="https://puck.nether.net/mailman/listinfo/boatanchors">https://puck.nether.net/mailman/listinfo/boatanchors</A><BR>>
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