Well from experience, many fans have a "lifetime warranty". Now from my
take, when the fan fails that is the end of its life and thus the end of the
warranty. Same for "lifetime lubrication" in my thinking.
Why did the fan become noisy? Likely due to bearing wear, thus due to lack
of lubrication. I just finished a SB-220 in which the fan was squalling
like a Banshee. Cleaning and a couple of drops of oil will keep it alive
for a few more years.
From experience with broadcast transmitters from the '40's to current day
power amps, proper cleaning and lubrication is the key to keeping things
running. For example, loosing cooling is certain death to either of those
items. Of course many BC transmitters have air flow sensors and switches
that will shut things down when the cooling fails.
Interestingly, we hams insist on amps to which the fans make little to no
noise. So since these do not usually have airflow sensing, and hopefully
they are very quiet or we are wearing headphones, how do we know we've lost
cooling? Usually when smoke comes out of the box.
ASSUME ??? Don't ever do this! Break it down to 3 syllables: 3
letters 1 letter 2 letters Now what do you have?
73
Bob, K4TAX
----- Original Message -----
From: "Mike Pagel, K9UW" <k9uw@wi-net.com>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Sunday, February 02, 2014 2:50 PM
Subject: Re: [TenTec] Care and Feeding of Centurions
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 service.
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
needed.
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.
73
Bob, K4TAX
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