[Boatanchors] #44/47 Buld replacement with LEDs
Michael A. Bittner
mmab at cox.net
Fri Feb 4 23:04:20 EST 2011
Thanks Gary, that clears up some questions. I'd always heard that damage could be done to an AA5 if a burned out pilot bulb were not replaced.
Next question: Should a 35W4 always have a pilot bulb connected, as in an AA5, for proper operation. My Knight Ocean Hopper has a 35W4, but no pilot bulb.
----- Original Message -----
From: Garey Barrell
To: boatanchors at puck.nether.net
Sent: Friday, February 04, 2011 7:38 PM
Subject: Re: [Boatanchors] #44/47 Buld replacement with LEDs
The 'tap' on the filament is NOT a 'center tap'.
The problem with this system is that of course the bulb is subjected to
the initial surge of current when filaments are cold, causing that flash
that you see at turn-on.
Worse still is that when the bulb inevitably burns out, the excess
current is forced through that portion of the filament in the rectifier,
causing it to fail open. LOTS of rectifier tubes killed when the owner
noticed the bulb was out, but didn't want to take the radio to the shop
for repair! Then he got to pay for a bulb AND a tube! :-)
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
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