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

Robert and all

Re   "I am no expert but I believe you can't rely too heavily on any tube tester. "

 

Well if it "reads bad" it likely  is bad.   

 if it "reads good" it may well be   good  under the condition it is being tested at.   

Most TTs  measure Gm  [where amplification is part of the intent in the tube.]

If you have a variable Mu tube  you really want to know if it works properly with a small bias. But you want it to also work properly at a large negative bias

.. if you don't test it down there   you might not know it has too hi a gm ..  maybe that is where the gas messes things up  like Jacques said.

I recently saw other  postings somewhere the front end tube tested ok …  but did similar things

.. but we need to get the books out on the details

 

 

 

From: Amateur-repairs@groups.io [mailto:Amateur-repairs@groups.io] On Behalf Of Gary WB6OGD
Sent: Friday, January 19, 2024 11:58 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