RE: Star Wars - flyback suggestions?

On a slightly related note, does a cracked flyback mean it's bad? I just
got a WG 6100 (Color XY) HV cage with a flyback that has a small chunk of
plastic missing and a hairline crack halfway down the side. There is no
black tar oozing out of it, and all the components seem fine. I was just
wondering...I really don't want to spend much time on something if it's
definately killed. Thanks!!!

Ed

(Alright, it's not a flyback, but an HV transformer.)

On Mon, 17 Aug 1998, Clay Cowgill wrote:

> > Er... I still don't nesc buy it. A shorted winding or two on the
> > primary
> > will be very obvious with a meter, and it may be trickier on the
> > secondary....
> >
> > but a wrap or two on the secondary won't make the flyback unusable...
> > and
> > if it is a short across (for instance) a significant portion of the
> > secondary coil, the resistance will show it.
> >
> > The only failure mode I can think of that a live test (with a high
> > freq.
> > signal) might get above and beyond a meter test is a bit of insulation
> > in
> > the secondary that has broken down (fine under no power, but a high
> > voltage arc in the secondary when in operation).
> >
> (I bet insulation breakdown in the windings is the #1 problem, at least
> in GO-7 flybacks...)
>
> The DVM-only technique seemed to work on my WG6100 flyback, so I was
> "sure" it would work on GO-7 flybacks too... My test case was about 20
> (23?) GO-7 flybacks (done about a year ago-- found a bunch of chassis'
> in the trash :-). I used a pretty nice bench meter at home (a Fluke
> 8000 series) and determined that 4 were definately bad (like blown in
> half and leaking "tar"), and the balance were "probably" OK compared to
> my brand-new "reference".
>
> I knew this *wasn't* likely, so I took 'em in to work and used the
> Sencore's flyback test function. Out of the 19 "probably OK" flybacks I
> had 7 that were actually good. The balance-- 12 -- were all dead.
> Verified by testing a handful in different chassis until I was convinced
> that the Sencore wasn't lying...
>
> As I recall there was a good bit of "difference" from flyback to flyback
> compared to the "reference", and with very low resistances to begin with
> it was too tough to tell changes of milli-ohms. You might be able to do
> it with a VERY accurate ohm-meter, but from my hands-on test the flyback
> test/inductor ringer was the only definite way to spot the problem
> flybacks...
>
> -Clay
>
Received on Mon Aug 17 17:19:42 1998