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

Dotan Cohen dotancohen at gmail.com
Wed Dec 10 14:11:30 UTC 2008

2008/12/10 David Fletcher <dave at thefletchers.net>:
> On Wednesday 10 Dec 2008, Dotan Cohen wrote:
>> 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?
> We were talking about power supplies and the testing of them a couple of weeks
> ago.

I will STFA, thanks.

> It's not only the accuracy of the output voltages that need to be tested.
> There is another output from the power supply that is a signal to the
> motherboard that tells it that all the output voltages are stable, and that
> it is OK to boot.
> If this signal is not working (and in my limited experience of faulty power
> supplies this is the case maybe 50% of the time) then even though the
> voltages are correct the computer will not boot, because it's being told not
> to.

I never knew this, thanks!

> So, go buy a proper PC power supply tester. They're cheap and well well worth
> the money. I repeat here the link I provided before:-
> http://cpc.farnell.com/CS14742/computer-products/product.us0?sku=thermaltake-a235b
> This is not the same model I have which has gone out of manufacture probably
> due to RoHS, but I'm sure it will do the job. Mine also has convenient probe
> access points, in case you still want to poke it with a DVM.
> Dave

Thanks, I will look into a dedicated tool. Take care.

Dotan Cohen



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