Testing PSU with multimeter (Was: Problems with kwin and kwallet.)

[Dotan Cohen]

2008/12/10 Barry Premeaux <bpremeaux at gmail.com>:
>> How do you load up the PSU when testing with a mutilmeter? I've caught
>> one bad PSU with a multimeter but I have another one suspect that
>> shows fine on all leads. I suspect that if I could load it somehow I
>> would catch it dropping voltage. What draws 300-500 watts yet is safe
>> enough to plug around the different leads? Five lightbulbs? I don't
>> suppose it would matter that the PSU is DC, but can you tell me
>> otherwise?
>
> If I had it in the shop, I would get the specifications for each
> voltage it puts out to determine the maximum current rating for each
> one.

That's usually printed on a sticker on the side of the PSU.

> Then with the old ohms law (R=E/I), I would pick up some high
> wattage resistors (500W) at values slightly higher than the calculated
> values.  This would give me the appropriate load for each voltage that
> would put me near max current draw.  Then I could watch the outputs on
> a scope (or meter) to see if they start to roll off with load.
>

I might try that some time, but I wouldn't take the thing to max load,
maybe only 50% or so. I have a lot of resistors lying around that I
could experiment on. I still remember phone numbers as coloured bands!
(obligatory xkcd referrence in every OT thread)

-- 
Dotan Cohen

http://what-is-what.com
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