[Collins] 32V-1

[Dr. Gerald N. Johnson]

On Sun, 2007-12-16 at 09:00 -0500, Phil LaMarche wrote:
>  This morning my dowkey relay failed and didn't mute the 75A-1.  Quickly
> unkeyed but smoke rolled out of the receiver and no audio.
> 
> Guessing the ant coils smoked but won't know till looked at.  Can anyone
> advise if these coils can be found anywhere>  I had a SB221 in line as well.
> 
> Phil
>  
Ought to be only one antenna coil smoked. Just for the one band. Just
failing to mute shouldn't have done in the receiver, unless the
transmitter arced across the open RF contacts to put RF on the receiver
(and antenna) directly.

One smoked antenna coil shouldn't kill receiver audio or other bands
unless continued audio feedback overworked the audio output tube or
audio output transformer, but I've seen 6V6 screens glow red without
permanent damage.

It may take good archeology to determine the construction of the
original coil, probably low frequency and PI wound?  Likely its a
variation on a stock slug tuned coil from a place like J.W. Miller with
a custom inductance and an antenna link winding. Extracting the smoked
coil from the radio while leaving enough to do that archeology will be
the trick.

-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer