[Amps] TL-922(A) Recent Acquisition

[Bryan Swadener]

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 regulated
and switched bias is also part of the deal. When you make your purchase, complete
documentation is supplied, along with a link to the Bill Of Material on Mouser's website.

Many hams have used Jim's boards to convert various ham amplifiers. I like the similar
board for my SB-220.

vy 73,Bryan WA7PRC


     Date: Sun, 27 Nov 2016 07:30:28 +0200
From: Vic Rosenthal <k2vco.vic at gmail.com>
To: Jeff Breitner <lists at rudn.com>
Cc: amps at contesting.com
Subject: Re: [Amps] TL-922(A) Recent Acquisition

I would definitely replace it with vacuum relays, or a vacuum relay plus a reed relay.
The stock relay tends to hot switch with semi-QSK CW and SSB VOX. It isn't worth saving.

Vic 4X6GP

> On 27 Nov 2016, at 00:08, Jeff Breitner <lists at rudn.com> 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.
> 
> Jeff