[TenTec] anyone lose a centurion hv xfmr?

[Mike Hyder -N4NT-]

I had a questionable HV transformer in an SB-220.  I applied low voltage (6 
or 12 VAC) to the secondary to see if I got voltage across the primary.  No 
big voltages here.

I say without knowing that your secondary resistance ought be far less than 
1K.

73, Mike N4NT

----- Original Message ----- 
From: "John (KE5C)" <ke5c at hot.rr.com>
To: "Ten-Tec Reflector" <tentec at contesting.com>
Cc: "Steve Bosshard (NU5D)" <bosshard at gmail.com>
Sent: Wednesday, April 12, 2006 2:32 AM
Subject: [TenTec] anyone lose a centurion hv xfmr?


> the short question is, does anyone know the approximate secondary 
> resistance of
> a centurion hv xfmr?  the reason i want to know is that i am trying to 
> determine
> if i've lost my centurion hv xfmr without actually measuring the secondary
> voltage.
>
> the full story is that i had the amp on but not in use.  i thought 
> something
> fell down in the shack due to an unusual noise.  everything looked in 
> order, but
> then i noticed the amp was off and one of the line fuses had blown.  i 
> took the
> cover off and saw nothing unusual and decided to replace the blown fuse 
> and put
> the cover back on.  this seemed to bring the amp back to life, so i put it 
> in
> line and turned the orion down to about one watt and keyed.  all seemed to 
> work
> (i am using a qsk loop), so i advanced the drive to 20 watts and 
> fortunately i
> was monitoring grid current because it went sky high in a hurry.  i 
> switched the
> meter to hv, and there was none.  after some *extremely* careful
> troubleshooting, i determined the hv primary is receiving 230 vac, but i 
> have no
> way (and little courage) to try to measure the transformer secondary 
> voltage.
> however, the secondary resistance (with the rectifier board connected) is
> initially more than 1k ohm.  the apparent resistance falls with time due 
> to the
> capacitors charging via the vom, and reversing the test polarity restores 
> the
> resistance to more than 1k ohm until the other bank of capacitors start to
> charge.  this also suggests to me that both sides of the full wave bridge 
> are
> intact.  hence, i am thinking i may have an open hv xfmr secondary, 
> although why
> would that blow a fuse???.  i don't know what the xfmr resistance should 
> be, but
> certainly less than 1k, right?
>
> thanks for any comments, john