[TenTec] Issue with Centurion

Floyd Sense floydsense at gmail.com
Tue Oct 24 12:33:19 EDT 2023


Hi Ted.  I have a Centurion now and have had a couple of others in the 
past.  First question: how are you measuring the 600 watts?  I suggest 
using a constant carrier mode so there's no confusion about peak reading 
or average reading wattmeters.  The 6 pots on the display board that are 
used to calibrate the meters are really poor and almost impossible to 
adjust properly when calibrating the meters.  I have replaced all 6 pots 
with multi-turn Bourns pots - those are easy to adjust and unlike the 
original pots they will hold the adjustment.

It's always a good idea to adjust the Centurion meter and bar LED power 
readout using an external wattmeter of known accuracy.  I use an 
LP-100.  The plate current and grid current meter scales should be 
calibrated using the procedure given years ago on this forum.  If you 
can't find that, I can send you info and photos. That calibration is 
done with no power to the Centurion.

You won't get any more power out than what  you're seeing if driving 
with 25 watts.  To get to a KW out requires 50 watts on 160 meters and 
gradually increases to 75 watts on 10 meters.  Some use as much as 100 
watts drive.  Guess it depends somewhat on the tubes and of course your 
skill in setting the load and tune controls.  When you say "excessive 
plate current", exactly what level do you consider to be excessive?  
And, keep in mind that your plate current meter could be far out of 
calibration.  The stock adjustment pots will change settings with 
vibration and shock from shipping over the years.

One other thing, adjusting some of the meter pots requires you to remove 
the cabinet.  Whatever you do, don't allow the high voltage safety 
interlock lever to contact the HV terminal when there's still HV 
present, even with the Centurion powered off.  Doing so will likely 
damage the bias transistors.

73, Floyd - K8AC



More information about the TenTec mailing list