[Hallicrafters] HT33B HV transformer problem

[gkb]

If this transformer has a dual voltage primary, here is what you do. Put an
AC meter across both primaries. Hook up a variable AC supply to the ends of
the HV side. Bring it up so you can see some voltage on the meters, primary
side. Compare the two meters. If there is a significant difference, you have
a short or an open.
Regards,
Gary...WZ1M
----- Original Message ----- 
From: "Rodger" <WQ9E at dtnspeed.net>
To: <hallicrafters at mailman.qth.net>
Sent: Sunday, January 14, 2007 12:42 PM
Subject: RE: [Hallicrafters] HT33B HV transformer problem


Also see:  http://repairfaq.ece.drexel.edu/sam/flytest.htm#flyoftp this is
specifically written for flyback transformers but is also applicable to
other low frequency (power and AF) transformers. Look under method 1 for
testing using reduced "Q" to determine if shorted turns exist.  I recall
reading about a similar method using an audio oscillator to excite the
primary, if it had shorted turns the oscillator would be loaded so heavily
that it would be unable to build up significant voltage across the primary.

Again use extreme caution when testing this type of transformer, even
testing with an ohmmeter will generate significant voltage when the magnetic
field collapses (think vintage automobile ignition systems).


Rodger WQ9E


> Subject: [Hallicrafters] HT33B HV transformer problem
>
> Hi guys. My buddy has an HT33B. We suspect that there is a short in the
> HV
> transformer primary winding. Is anybody in a position to measure the DC
> resistance of a known-to-be-good transformer primary? That would help us
> confirm our suspicions. Thanks very much for any help.
>
> Ken Grant, VE3FIT.
>  ve3fit at rac.ca.
>
>
>
>
>
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