[TenTec] Centaur problem ?

[Michael Melland]

I've been having a problem with my "new" used Ten-Tec Centaur amp.  I
can tune it easily on all bands except 15 meters to about rated power. 
On 15 meters about all I can get is 200 watts (freshly calibrated Bird
43 and Autek meters).  I've followed the tune-up procedure to the letter
but noticed this problem right away.  After about two hours use several
weeks ago there was a "big bang" and the main fuses blew while tuning up
on 15 meters and the center tube quit working.  I sent the amp back to
Ten-Tec with a note on the problem and a follow-up phone call.  I got
the amp back yesterday with a new center tube installed and a note
stating it checked out fine with output to 500 watts on all bands into a
50 ohm load.  I hooked it up again and still find max out on 15 meters
of 200 watts....... all other bands are in specifications.  I tried
disconnecting the ground thinking ground loop but same results......
tried direct into a dummy load , same results too.  Checked out my
exciter (Omni V) which shows 90/100 watts into antenna or dummy.  My SWR
shows under 1.5:1...   There does not appear to be excessive swr into
the amp input and reflected power between amp and rig is low.  I'm
lost..... anyone else have any ideas what could be affecting my 15 meter
output ??  Bad coax is all I can think of but why only one band ?  

73 de Mike, W9WIS
-- 
Michael Melland, W9WIS
Winneconne, Wisconsin, USA
FISTS #4387, 10-10 #69281, QRP-L #1656, 
QRP-ARCI #9875, AK/QRP #478, NorCal
CW, SSB, and Electronics
List Administrator: grundig@qth.net
http://www.qsl.net/w9wis

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