Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

Not familiar with it at all, so this is just a guess.  But perhaps to create a smaller magnetic filed around the filament leads?  1 amp vs 4 amps means much small magnetic field.

 

Again, just a guess

Will N4JBD

 

On 01/21/2024 11:58 AM CST Robert Lonn WA6PHN <roblonn@cox.net> wrote:

 

 

Not sure Electrically why Collins did this type of Filament set up, but it must have been for a very sound engineering reason..

 

This is a link to a short 1 minute Video of the filament circuit and 25.2 Volt AC power transformer. If your familiar as to why this was done this way, it would be appreciated to share your knowledge.. The KWM-2A has a somewhat similar setup for some of its tubes..

 

Robert WA6PHN

 

From: Amateur-repairs@groups.io [mailto:Amateur-repairs@groups.io] On Behalf Of Gary WB6OGD
Sent: Friday, January 19, 2024 8:58 AM
To: Amateur-repairs@groups.io
Subject: Re: [Amateur-repairs] Creating a LSB and USB Test Signal!!

 

Robert,
Good advice.
I am no expert but I believe you can't rely too heavily on any tube tester.  The actual circuit where the tube goes is the best tester.

I downloaded the 51s1 manual just to have a look.  The BFO is one tube.  I would try another, there are probably many types that could substitute
there if you don't have a good spare.  I am thinking it maybe has a filament to cathode short or leakage of some kind that lets the AC filament signal onto
the BFO signal.  But just a guess.
73,
Gary
WB6OGD

 

 

Grownups  never understand anything by themselves and it is tiresome for children to be always and forever explaining things to them,

 

Antoine de Saint-Exupery in The Little Prince