Re: Star Wars - flyback suggestions?

Hi Ed!

This is probably a FB with a shorted turn. It has overheated and shortly
will take the horizontal output transistor and maybe the regulator when
it croaks. I would really recommend that you replace it now!

John :-#)#

Ed Henciak wrote:
>
> 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
> >

-- 
 John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9     
 Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)  
 mailto:jrr_at_flippers.com, web page http://www.flippers.com      
        "Old pinballers never die, they just flip out."