Vacuum/reed relays are the way to go. The W7RY QSK relay driver board provides
all the support needed. Jim sells the bare TL922(A) board for $18:
http://www.ebay.com/itm/282199995256. He offers the reed relay to switch the
input, and recommends Max Gain Systems as a source mfor the vacuum relay
to switch the output. Your rig has to switch only 10V @ 1mA. Electronically
and switched bias is also part of the deal. When you make your purchase,
documentation is supplied, along with a link to the Bill Of Material on
Many hams have used Jim's boards to convert various ham amplifiers. I like the
board for my SB-220.
vy 73,Bryan WA7PRC
Date: Sun, 27 Nov 2016 07:30:28 +0200
From: Vic Rosenthal <firstname.lastname@example.org>
To: Jeff Breitner <email@example.com>
Subject: Re: [Amps] TL-922(A) Recent Acquisition
I would definitely replace it with vacuum relays, or a vacuum relay plus a reed
The stock relay tends to hot switch with semi-QSK CW and SSB VOX. It isn't
> On 27 Nov 2016, at 00:08, Jeff Breitner <firstname.lastname@example.org> wrote:
> Update on the recovery.
> Amp powered up, everything on the HV side and tube side looked good, or as
> good as I expected. Was able to key the amp with no drive and see idle
> plate current, amplifier didn't do anything unexpected in the hours I let
> it run.
> However, when it came time to apply some RF, a check of the input showed it
> to be open. I recalled during the inspection that there had been plenty of
> activity around RL-1, antenna relay. Sure enough, there was enough
> Cramolin residue on the inside part of the relay, and the spring was
> missing. Contacts cleaned up seemingly good enough, but without the spring
> that is nothing.
> It appears the MM2 relay is still available, for a healthy $180 or so,
> although I think this can be salvaged if I can find some sort of spring.
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