[rescue] Power supply repair (was: Tektronix XP350 & IRIX questions)

[Tim H.]

On Mon, 15 Jul 2002 09:03:05 -0500
Scott Newell <newell at cei.net> wrote:

> Please don't forget the isolation transformer!  If you don't know what
> one is, or why you need it, I would suggest that you not 'scope around
> an offline SMPS.
> 
> 
> newell

  Of course everyone knows there's nothing in that little box that can
hurt you, the wires are too small. :-)

yeah, use an isolation transformer, which is a pretty good idea when
working on any electronics, even piddly-squat wall wart stuff, because
an amazing number of wall warts are not isolated and are not polarized.
An unexpected 110V out of a 6V wall wart will get your attention. 
Isolation transformers are one of the things that pros forget about
cause they always use them, and hobbyists don't learn about until they
let some magic smoke out, or light themselves up.

all electronics http://www.allelectronics.com has a little naked
isolation transformer for $9.75, throw it in a box with an outlet and a
power cord and you're all set.  Only 100VA (a hair under 1 amp at 110V)
but that would be fine for powersupply troubleshooting.

Tim