Variac

[J Forster]

That's what line fuses are for. If a cap goes bad, the line fuse should be sized to
blow. Slo-blow is needed because of inrush currents to the caps and cold filaments.
Properly sized, you might loose the rectifier tube, but not the transformer.

-John



Jim Bowman wrote:

> I have wondered of it is possible to insert a fuse of some kind
> (slo-blo?), that would handle the normal surge, in series with the caps
> connections so that the fuses would blow if the caps ever shorted, and
> would prevent damage to the transformer, etc?
>
> 73,
>
> Jim W7HPK
>
> "L.G. Robertson" wrote:
> >
> > There are many who feel this way...but if that reformed electrolytic blows
> > (and they can), it might drag the transformer and (if the set has one) the
> > electrodynamic speaker field coil with it, etc etc.  Now you have to
> > replace the electrolytics anyway, AND maybe a transformer (_if_ you can
> > find the right one), speaker field coil, etc etc.
> >
> > _Now_ how much is that non-glowing, non-working firebottle box worth?
> >
> > The general ethic I use is that if the electrolytics are above the chassis
> > line, I leave them in place, remove them from the circuit, put in new ones
> > _underneath_ the chassis, and leave the old outer shells in place.
> >
> > Or, for a real purist approach, if the situation calls for it, I take the
> > old "innards" out of the electrolytic, put new, miniature types inside, and
> > seal the whole thing back up with the original wax, seals, etc, and then
> > use the appropriate type of wire to complete the hookup.  To look at it
> > you'd never know there were new caps inside the old shells.
> >
> > -Lin/KJ6EF
> >
> > At 06:28 PM 01/31/2008, you wrote:
> > >IMO, restored gear is a lot less desirable than original antique gear. Hence I
> > >don't recap.
> > >
> > >-John
> > >
> > >
> > >
> > >L.G. Robertson wrote:
> > >
> > > > At 01:30 PM 01/31/2008, you wrote:
> > > > >I have come to the opinion that I should just plan on changing the
> > > > >electrolytics for new ones even before I bring up the radio. Haste makes
> > > > >waste. If the cap(s) don't fail now they will probably fail pretty soon so
> > > > >just go ahead and change them out right at the start.
> > > > >
> > > > >Bob, WA2CKY
> > > >
> > > > Same here, after 40 years of fooling with 'em...you can get away with
> > > > reforming them _sometimes_...but it still makes me a tad nervous to run a
> > > > rig with reformed electrolytics....it's always in the back of your
> > > > mind...so I mostly just replace them; they're usually not too expensive.
> > > >
> > > > But transfomers ARE.
> > > >
> > > > -Lin/KJ6EF

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