[TenTec] Care and Feeding of Centurions

Mike Pagel, K9UW k9uw at wi-net.com
Sun Feb 2 15:50:18 EST 2014

QST published an article called "Amplifier Care and Maintenance" in 
September of 2003 and it is available (as a PDF) to members on their web 
site.  The article includes a flow chart for diagnosing problems.

My Centurion is ~1992 vintage and I bought it used.  To date, I've replaced 
several components.  The tubes were first (after dropping one of them while 
unpacking the amp the day it arrived!).  The original fan became noisy so it 
was replaced.  A couple of years ago, operator error resulted in a damaged 
variable capacitor (Tuning), which I replaced with guidance from Jim Rogers 
at TenTec.  Jim provided superb support to this appliance operator, and I 
was able to handle the job without shipping the amp back to TenTec for 

For some reason, Bob, I had assumed those fans were not to be lubricated. 
Guess I'd better get in there.....

73, de Mike, K9UW
Amherst, WI

-----Original Message----- 
From: Bob McGraw - K4TAX
Sent: Sunday, February 02, 2014 2:03 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Care and Feeding of Centurions

First, disconnect the power.   The voltage in this unit will KILL YOU!

Once a year, remove the case and covers.  Be sure the HV shorting strap/bar
is in tact and does short the HV supply.  This is when the unit is being
serviced and out of the case.

Clean the fan blades, add one drop of 3 IN 1 oil to the shaft bearings.
Take care not to bend any of the fan blades.    Clean any dust from inside
the case using one of the "computer type" compressed dusters.  Look for any
discolored connections, discolored areas on the PC boards and, specially at
the base of the tube sockets.  If any exists, replacement or repair is

Put everything back in place and do install ALL of the screws.  The amp is
ready for another year of working DX.

Proper tuning and loading and proper drive is the key to success for long
amp and tube life.

Bob, K4TAX

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