[Amps] Help with AM-456A/TRA-19 amplifier

Paul Hewitt wd7s at earthlink.net
Mon Nov 23 13:36:09 EST 2015


Hi Larry
Have you tried calling Fair Radio??  They have a huge inventory military
stuff not listed in their catalogs.
Paul 

Paul Hewitt
WD7S Productions
QRO Homebrew components
http://home.earthlink.net/~wd7s/contents.htm

-----Original Message-----
From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of larry
Sent: Sunday, November 22, 2015 6:31 PM
To: amps at contesting.com
Subject: [Amps] Help with AM-456A/TRA-19 amplifier

   Hello all, I'm trying to resurrect this amplifier I found today at a
local antique store. It appears to be for the 222MHz band, and uses a 4CX250
tube. It is currently missing several tubes in the Power Supply section
(V101, V102, V103 which look to be the rectifier tubes, and V105 which I'm
guessing is maybe the time delay), and I could not locate anything of value
on the web as far as schematics go. I took a peek underneath the PS to see
if it's been updated with diodes, but there isn't anything extra added.
Plus, there are 4 wires connected to V101 - 2 coming from the transformer,
and 2 leaving and connected to V102. It appears to have been modified for
the Amateur frequencies already or was in the process of being done, and I'm
hoping it's on 222. Would someone have any idea what tubes I could use in
this old beast, or a conversion article or tips on upgrading old military
power supplies to SS? The transformer has a 1500V secondary if that helps
any.

It looks like I've found my winter project ;-)

Thanks for your help,
Larry
N1MIW
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