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

From: Joe R. <rigdonj_at_cfl.rr.com>
Date: Tue Nov 16 10:41:42 2004

At 11:15 AM 11/16/04 -0500, you wrote:
>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.
>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.

  OK I just picked up some computers with 150 Amp 5 volt supplies. Now figure out the necessary resistrance and wattage and go find me a resistor :-)


>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.
>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 - 10:41:42 GMT

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