reforming PS caps w/primary-side components

From: Bill Yakowenko <yakowenk_at_yahoo.com>
Date: Mon Jun 2 22:17:00 2003

Anybody want to offer advice on reforming filter
caps? I'm planning to power up some stuff that
hasn't seen voltage in a long time. My plan is
to put several low-wattage light-bulbs in series
with the thing, to limit the amount of current it
will get, and hopefully allow those old caps
to reform instead of, say, exploding in my face.

It would be better to put the light bulbs (or
whatever kind of resistor) in series with the
caps themselves on the secondary side of the
transformer, right? But if I start digging into
the thing's innards like that, there is a real
risk that I'll damage it more than an exploding
cap would. (In one item, there is a picture
tube nearby, and I'm sometimes clumsy...)

Now the questions:

Could putting the light-bulbs (or whatever) in
series on the primary side of the transformer
actually produce the desired effect? IIRC, a
step-down transformer divides the voltage but
multiplies the current. So I'd have to limit the
current on the primary side that much more to
keep the secondary current down, right?

Also, what kinds of things could be damaged by
getting less voltage than they were designed for?
I could imagine hard disks spinning too little to
lift the heads from the surface, for instance.
(This is moot, because there are no hard disks
in any of the equipment I'm looking at.) How
about CRT's? Could too little deflection make
the beam hit something it shouldn't? Anything
else?

        Thanks,
        Bill.
Received on Mon Jun 02 2003 - 22:17:00 BST