how is a psu tested

[grassy]

If a power supply is faulty how is it tested. I understand that a multimetre is used, but is there a way of testing it under load without it being hooked up to your computer. Also is there more than one way of getting to the nitty gritty of a power supply problem. Thanks

[peanutz94]

Generally a PSU is tested on a machine something like this

http://www.chromausa.com/automatedtestsystems.php#8010pc. I can't remember off hand what model Corsair uses but it is similar. I believe Jonnyguru posted the model they use at one point but I can't seem to find where that info is exactly at.

 

You could still test a PSU under load while in your computer using spare molex or SATA connectors and take the reading of the three rails that way.

Other than that it would be hard to test a PSU under load outside of the PC. Without one of the industrial PSU testers it's just about impossible to simulate real world usage or power demands.

[grassy]

Thanks Peanutz94, i am having some issues starting my pc after turning it of at the power supply and then trying to turn it on in the morning and it wont turn on.The only way to turn it on or get it going again is to take the computer apart and put it back together again. The computer is outside the case at the moment and still wont turn on.If i leave the power supply on during the night it will turn on the next day otherwise it wont. I just thought i would ask the question as i am thinking of taking my power supply in for a proper test. I did notice that in my bios that one of the voltage readings were in the red at one stage and then it came good and is no longer in the red. Also when it was in the case a case fan would struggle to get going on start up.

[peanutz94]

I did notice that in my bios that one of the voltage readings were in the red at one stage and then it came good and is no longer in the red. Also when it was in the case a case fan would struggle to get going on start up.

Which one is showing red? Im going to guess and say it's your 3.3v rail that is reading low. That is a pretty common thing when that rail is low. The others can also cause it, but in most situations like this it's the 3.3v rail.

 

There are other testers that are available on the market , but generally they only read the present voltage and not what you would need to put an actual load on the PSU . Just to add to that Ram Guy has stated a few times that the commercially available PSU testers may not read properly with their PSU's because of the components used in them.

 

The only other way to really say for sure is to test it with a another known good PSU. That would tell you for sure. And if another PSU does the same thing i would say it's a MB issue.

 

In any case given the symptoms and the BIOS reading i would put money on the PSU as your problem child. :)

[grassy]

your absolutely correct it is the 3.3 so what does that mean now. I am flat out trying to find a psu big enough to test.I have a 1200 watt power supply and have tested the system with a 850 watt and it did not start. So i am thinking it might be a motherboard problem.

[peanutz94]

If the 850 is a known good PSU then I would tend to think it's the MB.

 

However you could always RMA your current PSU and that would give you a definitive answer.

[grassy]

Thanks peanutz, i will do just that and am very greatful for your support. Thankyou