Re: {Collins} (no subject)



YOU may be fine, but your electrolytics won't be.  The one, and only, way
to reform an electrolytic is to disconnect it from the circuit and gently
apply current, never exceeding a few mA, until the working voltage is
reached.  Repeat for each section of a can.  This process can be done with
a bench supply, limiting resistors, and meters; or use a capable capacitor
tester.  An alternative is the method Bill described in an earlier
posting:  remove all tubes and rectifiers, and apply current to all
sections of the supply electrolytic at once, through the B+ filtering.  The
problem here is there's no way to tell which section of the electrolytic is
getting which fraction of the current, so it'll take just as long.

As Bill described in detail, 'bringing 'er up on a variac' will spell
disaster for the power supply electrolytics..  Ask me how I know... :)

73, John K4OZY



On Wed, Oct 25, 2017 at 6:11 PM, Francesco Ledda via Collins <
collins@xxxxxxxxxxxxx> wrote:

> Put a 200W lamp in series. It will protect the radio and the variac. As
> you crank up the variac, look at the lamp filament. As long as the bulb
> doesn't get bright, you are fine.
>
> Sent from my iPhone
>
> > On Oct 25, 2017, at 11:36, W6ph--- via Collins <collins@xxxxxxxxxxxxx>
> wrote:
> >
> > Put an appropriately rated fuse between the variac and the radio.  If
> > there is a direct short in the radio, the current going through the
> small wire
> > in the variac can burn out the winding.  Protect your variac.  Don't
> ask me
> > how I know.
> >
> > 73, Kurt W6PH
> >
> >
> > In a message dated 10/25/2017 8:51:28 A.M. Pacific Daylight Time,
> > collins@xxxxxxxxxxxxx writes:
> >
> > I'd  point out that, normally, most things don't start happening until
> you
> > get  to 100 volts -- and by then it may be too late. If you have a variac
> > that  measures current or some other ammeter that is always very  useful.
> >
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