Testing Power Supplies! Re: Norsk Data Nord-10/S restoration

From: Ed Kelleher <Pres_at_macro-inc.com>
Date: Tue Nov 16 10:15:26 2004

At 10:25 AM 11/16/2004, you wrote:
> Ed> Old disk drives, if they'll at least spin up, make good dummy
> Ed> loads. The AC setting on a voltmeter will let you know if you
> Ed> have too much ripple on a DC supply.
>
>Depends on the voltmeter...
>
>Actually, a resistor is a classic dummy load. They have the advantage
>of being dirt cheap, and readily available in thousands of
>variations. If Radio Shack doesn't hack it, Digikey certainly will.

Yup!
Well, for +12 and +5 you'll need two resistors though.
Power rating? [time spent pondering] 12v 1A = 12w, 5v 1A = 5w should do it.
Ooops, no 12 ohm or 5 ohm power resistors, got a bunch of 1 ohm ones,
so I can series/parallel a bunch of them ....
Screw it, they're not that much, maybe a couple of buck each.
Then connectors (what's the Molex part number?), and wires and heat shrink
and solder,
maybe a perf board to hold them, or a minibox

[project creep occurs, more features, more time, more money, CCTALK piles up]

then shipping expense (and time) from Digikey, or gas and AGGREVATION going
to RadioShack
["No, I already have a cell phone and Internet thanks, where are the
components, way in the back?"
then a wait at checkout as Granny gets a new hearing aid battery]

Maybe $10-$20 bucks,
Ooops, got to go back for the terminal lugs I forgot, or DigiKey was out of
stock on.

Vs.

Pull old XT2190 or ST251 from junk box,
plug in power supply lead, done.

Cost = 0, time = 1 minute, satisfaction at not having to go through above
nonsense = priceless!
(plus giving more time to keep up with CCTALK email and for composing
thoughtful email responses like this one! <g>).

:-)

I got an ATX power supply tester a few months back after a rash of bad ATX
power supplies.
Very handy.
Thought one for AT type power supplies would be good too.
Hey, just a few resistors for +12, +5 and some LEDS's, no sweat.
STILL working on it, or rather it's still not been done.

Got a box full of junk MFM drives, they work fine for this.

PLUS! the inductive loads and relay kicks from old drives might be better
than resistors anyway [thereby breathing more life into this thread].

Ed K.
    
Received on Tue Nov 16 2004 - 10:15:26 GMT