Electronics Forum / Repair / August 2008

--

On Aug 25, 10:38 am, "Arfa Daily" <arfa.da...@ntlworld.com> wrote:

Oh, I don't dispute that a BP will not pick up problems such as HV
breakdown, Jerry, but that is usually - or at least mostly - self evident in
that you can see the miniature lightning flying out of the pin hole, or
smell the ozone being generated, or see the effects on the screen as
brushing, or hear the effects on the audio, or even just hear it physically
hissing. The only point that I was making is that the BP unit is not a
'simple' reactance tester, but does a test which better simulates the
conditions that such a tranny operates in, when doing its normal job. Almost
any deviation from its correctly servicable parameters, will alter the way
in which the tranny rings, which will be picked up by the tester. Of course,
the results are open to a degree of experience and interpretation, in much
the same way as those from an ESR meter are, and a new, or at least 'known
good' tranny is useful to compare by, but never-the-less, the BP is a useful
tool even on its own, for picking up "most common defects", which is all I
was actually saying ...

Arfa

With any of these flyback checkers they will not show high voltage
breakdown, or critical problems with the flyback. This is only a
simple test!  I have been through this!

Jerry G.

But the Sencore drive tests catch most of them.  It applies a 25vp-p pulse
to the primary and you should get out 500-600vdc on most integrated
flybacks.  It is far better than ringing because it tests the high voltage
rectifier, if only at a fraction of the output.  It won't catch a leaky
insulator, but it will get most bad flybacks otherwise.

Leonard