Joe,
I'm hoping some of the other guys who are more "amp-saavy" than I chime in,
but you might be able to do a "cheap & dirty" test of the transformer this
way. It would be somewhat subjective, but disconnect the secondary and
tape/otherwise insulate the secondary terminal. Temporarily wire a table lamp
or lamp socket with a 100W incandescent bulb in series with the transformer
primary. Plug it in to 120V and apply power. If there's an orange glow the
transformer may be OK. If the bulb lights to near or full brightness there
may be a problem. (At least that's a good test for smaller transformers. It's
based on the fact that an unloaded/good transformer is mostly an inductive
load and thus won't draw much, but a transformer with a load on it or a
shorted winding will draw more and cause the bulb to be brighter.)
73, Al
On Tue January 26 2016 2:03:36 pm k8mp@aol.com wrote:
> Thanks Al. I think that's what is going on here.?I don't have a Hi-pot
> unit.?If I can't fix it easily (and cheaply), it's going back on the
> shelf...
>
>
> -----Original Message-----
> From: Al Gulseth <wb5jnc@centurytel.net>
> To: tentec <tentec@contesting.com>
> Cc: k8mp <k8mp@aol.com>
> Sent: Tue, Jan 26, 2016 2:54 pm
> Subject: Re: [TenTec] Model 411 amp (aka Centaur)
>
>
>
>
> Joe,
>
> Just an ohms check may not be enough. You may be dealing with an
> intermittent breakdown under high voltage. A "hi-pot" (high potential) test
> with an insulation tester etc. would be the only way to know for sure. A
> winding layer to adjacent layer partial short in the HV side could also
> account for your symptoms, and might not be obvious because the winding
> resistance could show right at the low edge of the manufacturer's spec. (I
> went through that scenario years ago with a HV filter choke in a small AM
> BC transmitter.)
>
> 73 es GL, Al
>
> On Tue January 26 2016 11:28:03 am Joe Papworth via TenTec wrote:
> > Thanks Andy. Was it the HV secondary that shorted?
> >
> >
> > I isolated the HV secondary from the HV board and it reads open to
> the > frame and chassis. (Reads about 45 ohms when connected to the
> board) >
> >
> > Thanks, Joe, K8MP
> >
> >
> > -----Original Message-----
> > From: P C Andy Anderson <xtraham58@hotmail.com>
> > To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
> > Sent: Tue, Jan 26, 2016 11:52 am
> > Subject: Re: [TenTec] Model 411 amp (aka Centaur)
> >
> >
> >
> >
> > Joe, I had a similar problem with my Centurion AMP. It eventually
> failed > completely. The secondary of the power transformer shorted to
> the frame. I > had the Xformer rewound at TRS. BTW this transformer
> problem is a known. >
> > 73' Andy, W3LI
> >
> > ________________________________________
> >
> >
> > Tuesday noontime, Joe:
> >
> > I have a Centaur..............keep it covered when not in use.
> >
> > My Elmer told me to always keep it covered..................dust is
> the > problem.
> >
> > Even when covered, open it up every two-three years and do a internal
> > cleaning.
> >
> > N1MHC/alsirois
> > =============
> >
> >
> >
> > Gents,
> >
> >
> > Have any of you gone a few rounds with a Centaur amp?
> > I have a one that blows fuses very intermittently. It vaporizes them
> both, > simultaneously, so it's apparently a dead-short somewhere. This
> happens > even in stand-by. (i.e. No key-down)
> >
> >
> > Before I tear into it, anyone have any ideas of common failures in
> these > amps?
> >
> >
> > Later, Joe, K8MP
> >
> > _______________________________________________
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> >
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> >
> >
> >
> >
> >
> >
> > _______________________________________________
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> > TenTec@contesting.com
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