Checking PSU with digital multimeter

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xpd

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#245653 14-Feb-2019 20:00

Either my video card died a few weeks back, or my PSU is at fault. A bus powered card runs fine, a dual 6pin card runs fine. But my dual 8 pin card wont run - fans tick over but thats it. I dont have a spare PSU to test with.

So pretty sure its the card but need to confirm before approaching SWMBO for a new card ;)

So if I pickup a cheap multimeter, whats the best way for me to check the pins on the PCI-e connectors are live etc ? Unplug from mobo, short the power to kick the PSU into life and touch the pins with the probes ?

Im not the best with electrical things as such :D

Computer geek yes, electrical geek, no.

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richms

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#2178518 14-Feb-2019 20:04

You need to test under load, but if the PSU wont power up with the card attached either the card is shorting it out, or the PSU can no longer deliver the power. Multimeter will tell you nothing much other than that there is no power coming out. And you can tell that already.

Ticking fans that are under motherbaord control can also be the motherboard not actually powering on, but a fan direct on the PSU that just ticks shows that the PSU isnt actually able to start up with the load connected to it.

Troubleshooting requires spare parts or paying a service place to figure it out, so either way you're going to have to spend something.

Richard rich.ms

Lias

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#2178545 14-Feb-2019 21:05

+1 to what @richms said.

It's been debated in many places over the internet, but my personal experience is that "age related PSU degradation" is a real thing. I've seen behaviour like you describe several times, and every time it was an older power supply that could no longer deliver it's rated load. Assuming the card itself isn't fubar, I'd be reasonably surprised if purchasing a new, good quality PSU didn't resolve the issue. Personally I'm a pretty big fan of Seasonic, either their own brand stuff or the higher end stuff that's re-badged Seasonic (e.g. Some higher end Corsair, XFX, Antec, etc.). They have a solid reputation, and as far as I am aware are the only PSU manufacturer that makes their own retail products, every other brand I know of is just contract made in a variety of OEM factories (Seasonic is obviously one of those and good, but many are not). As an example EVGA has had models made by HEC, Shenzhen Rui Sheng Yuan, Andyson, FSP, Super Flower and a few of their better units made by Seasonic.

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Rickles

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#2178591 14-Feb-2019 22:10

Try the card in another machine?

Gordy7

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#2178605 14-Feb-2019 23:17

One of these testers would be better than a Dmm...

http://www.overclockers.co.nz/store/index.php?
route=product/product&product_id=74

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xpd

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#2179712 15-Feb-2019 09:47

Sorry, i meant that when the GPU is connected, everything appears to fire up (can see drive access etc occurring) but just no video output.

So the PSU itself appears to be going. Its a Corsair VS550 IIRC.

@Rickles Im trying to organize that with someone but the other systems at my place don't have suitable PSU's to power it.

Im just in the position where I cant afford to buy a new card and find the PSU is at fault. :)

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Lias

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#2180680 15-Feb-2019 10:18

xpd:

Sorry, i meant that when the GPU is connected, everything appears to fire up (can see drive access etc occurring) but just no video output.

So the PSU itself appears to be going. Its a Corsair VS550 IIRC.

@Rickles Im trying to organize that with someone but the other systems at my place don't have suitable PSU's to power it.

Im just in the position where I cant afford to buy a new card and find the PSU is at fault. :)

PSU powering on, and PSU providing sufficient power on the 12v rails to power a higher end GPU are two entirely separate things. VS series are budget orientated, and made by at best average OEM's, so not one of Corsair's finer efforts sadly.

If I recall you're in the north of Auckland? Maybe take the GPU into Playtech and ask them if they can just power it up for you, and if it goes, buy a new PSU?

1101

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#2180715 15-Feb-2019 11:06

pretty much a waste of time trying to test with multimeter or cheap testing widget
You need to check all the rails under load, and look for noise/spikes .

It needs to be checked via an oscilloscope
Our work used to do that (and repair them) , now we dont bother scoping PSU's, we just replace . Thats the best test .

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xpd

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#2180814 15-Feb-2019 11:33

Lias:

PSU powering on, and PSU providing sufficient power on the 12v rails to power a higher end GPU are two entirely separate things. VS series are budget orientated, and made by at best average OEM's, so not one of Corsair's finer efforts sadly.

If I recall you're in the north of Auckland? Maybe take the GPU into Playtech and ask them if they can just power it up for you, and if it goes, buy a new PSU?

I could try that, but IIRC Playtech like charging for any form of testing ;) But yeah, will use that as last resort.

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richms

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#2181082 15-Feb-2019 19:05

xpd:

I could try that, but IIRC Playtech like charging for any form of testing ;) But yeah, will use that as last resort.

IME they will often credit that off the purchase of new hardware if you ask them.

Richard rich.ms

xpd

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#2181087 15-Feb-2019 19:13

Ive got a mate coming over tomorrow with his spare PC, so will know the easy way by this time tomorrow :D

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