[Hallicrafters] B&W TR Switch

[Parker Buckley]

A few years ago, I bought a B&W 381C electronic TR switch at
Hamvention.  Still in original box, with directions, appears never to
have been used.  I'm trying to use it between my HT-32B and SX-115, so
maybe this isn't too far off topic.  

Have any of you had any experience with these?  The unit seems to work
fine on receive, providing a little gain as expected.  On transmit,
however, it does not sufficiently mute the antenna line to the receiver
so I get a real blast.  I haven't tried the obvious tube checking;
somehow I doubt that's the problem.

I contacted B&W, and as expected there is no longer anyone there who
even remembers producing these units.

Thanks in advance for any possible suggestions.

Parker WD8JOL