Power Supply Problem

[John Heck]

Folks,
Mike Phillips makes a reference to the first application of power to a long out of
use boatanchor. I think this is a somewhat confusing matter for a lot of enthusiasts
and its importance deserves periodic review. We are all constantly accquiring new
junk to play with and the first thing anybody wants to do is put power to it. I think
the first thing you should do when you buy a new piece of gear is to cut the line cord
off. Do it when you put it in your trunk. That will assure that you will be forced to
dig into the power supply a little and do some thinking before you power it up. For
one example, it is my understanding that the old Variac/cap reforming procedure is
not at all correct. For one thing, vacumn tube power supplies do no begin to conduct
until some lower limit of applied voltage is reached, like 75-80v or so, and also that
electrolytics need to be reformed under constant current until they draw their rated
voltage at that current. This is not going to be accomplished with a variac, but needs
a bench setup of some kind to monitor current/voltage and supply about 600v AC vari-
able potential. I am *not* very knowledgeable about bringing up old gear, and I wish
someone who *is* would write us up a good procedure so we would have it for reference.
Would someone please do this for us??
Regards,
John Heck, KC8ETS
1009 Donson Drive
Dayton, Ohio 45429
(937)865-7036(work)
jkh at lexis-nexis.com

Mike sez:

> Were does someone find a Variac?
>
> I've experienced the same problem described, HW101/HP23B.
> Temporary solution was to swap power supplies, however, as my
> collection grows so does the need for fixing the wayward HP23B.
> Also, when powering up a purchase that may not have had power
> applied for a length of time, I know it is wise to use a Variac
> to allow electrolytics to reform. I've just never run accross a
> Variac at swap meets, etc., or didn't recognize what it was.
> Could some knowledgable soul educate me?
>
>                                     Mike (KE4HBA)

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