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Re: [Amps] Before I turn on my amplifier . . . . . .

To: <n3nd@aol.com>, <amps@contesting.com>
Subject: Re: [Amps] Before I turn on my amplifier . . . . . .
From: "Harold Mandel" <ka1xo@juno.com>
Date: Sat, 22 Jul 2006 09:21:08 -0400
List-post: <mailto:amps@contesting.com>
Dear Dan,

It might be wise to find out if there is a breakdown both in the power
supply section and in the RF deck before powering up with tubes
and drive.

Yank the tubes and disconnect the sections of the power supply. 

Use care.

Measure the anode transformer secondary voltage and verify
the absence of shorted or open HV rectifiers with a DMM.

Carefully verify the anode HV chain.

Use a piece of red silicon rubber under the new plate choke
to prevent easy arc paths.

See if your plate blocker cap is still good.

See if your choke's cold-end bypass cap is still good, too.

Check the reflector for all advice messages. 

Hal Mandel
W4HBM 




[snip]
I recently had an amp failure. Upon inspection, I found remnants of an 
arc between the bottom of the plate choke and chassis - which had 
jumped substantially across an insulator.  In the Ten-Tec Centurion 
amplifier, the plate choke is positioned immediately adjacent to the 
internal fan which blows across the choke and tubes.

The insulator between the choke and chassis was melted as well and my 
initial thought is that a critter had gotten itself across the chokes 
HV winding and chassis.  I have a replacement choke and insulator and 
am readying to replace them.  My question is, before I turn the amp on 
after component replacement, should I look for something else or is 
there concurrence that my suspicions have merit?

The original incident happened while transmitting.

Amp:  Ten-Tec Centurion
[snip]


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