Topic: When I add 2nd PSU it smeels like its catching on fire WTF!? BTC Tip for help! (Read 6553 times)

Yes, you don't want to do this. In effect you have two +12v lines pushing into each other(too many amps!! danger!).
Both PSU's +12v rails are connected/shorted technically. Do not do this, if you did this without the computer/-rail to take the electricity everything would go boom.

Thanks, man You shouldn't have. I just wanted to help a bit so you don't burn the house down

Essentially, BeetcoinScummer is right. Make absolutely sure you have good grounding. All the "return" of that power delivered will come back to only one of the PSUs if the grounding is not ok. Let us know how it smells after the changes

Steve

Yes, if it is a single-rail PSU.

You should also measure the power consumption of each PSU at the wall to see if the distribution of power is are what you'd expect. If you have uneven grounds you could end up having all the power to the rig being delivered by one of the PSUs.

Thank you I really do appreciate it I've had so many problems on this build finally see light at the end of the tunnel.

So by powering the riser with same PSU as mobo I should be good is what am gathering. Is this correct?

No need, advice is free -- you get what you pay for   (thanks though)

I will be tipping Grim, t13hydra, and CP1.

CP1 whats your btc addy?

Also to clarify the setup:
PSU1 = Mobo PSU

PSU1: Mobo, SSD, GPU1, GPU2

PSU2 = Multi GPU

PSU2: GPU3-GPU6, powered risers


Testing was done as follows:
 
PSU1: Mobo, SSD, GPU1
PSU2: GPU2, Riers

First of all thank you for all the replies!

Ok so the staples PSU was just a test! as stated earlier I had a 1000w bronze rated Kingwin PSU!

I did not know that the riser has to be powered through the MB's PSU this means I need a better PSU, mobo is currently pulling ~600-615watts and 75w x 4 would be 150 its only rated at 750 watts and NOT energy star rated.

I could still get another staples PSU and test a single or two GPUs, I ordered a 1k watt gold rated PSU and I'll grab a 850 watt bronze PSU.

Just for the record I'm returning the staples PSUs I'm just testing cause I dont want to burn through another PSU from amazon.

Could someone answer if I do not power the riser from the mobo psu would that cause a short like I'm seeing?

Do not forget to connect PSU grounds and check earthing.

Make sure you push the big red button first!

A staples PSU?  Seriously?  Take a picture of the side of the PSU where it lists the power ratings and post it here.

Just because the box says it has OCP (Overcurrent Protection), doesn't mean it works as it should.  Kingwin is meh as well.

I skipped over one part of this.  If the actual riser is heating up then there is too much current draw through it. 

Yep thats why I asked about how you powered your cards in detail.

The powered risers should be powered by your PSU1 = PSU plugged into your mobo

If your GPU is being powered half by the PCIe pins from PS1 and half by the riser-motherboard connection from PS2 it seems like you could have some weird ground loops in there.

Watch out for better quality riser cards. A high power draw can AND WILL overheat low quality circuits. Also clean the PCIe slots and make sure that the connections between the card and the slot offers a good contact area! Small contact areas with high load will also overheat. Lastly, beware of dust-balls. Specially dust + a humid enviroment: it makes mud! Literally. Dust is a good conductor, so get a good brush and clean the slots and the mobo for dust.

That's all i can say for now. Your PSU and/or riser is getting overloaded, not short-circuited. A short triggers the protection instantly, no matter how small. An overload kills the psu slowly and painfully (killing stabilization components first, then shorting out, then blowing the fuze, etc).

Regards and good luck!

Thanks for the reply so there would be a short circuit on two separate risers? The first was a Kingwin KX-1000 Watt PSU, 80 Plus Bronze, brand new specific for this build. Second was an antec from staples which was just energy star 80 plus.

I powered the riser with PSU #2 so the second card was completely on PSU #2 from the two 6pin power connecters to the powered riser. I'll see if tomorrow or the next I can return the PSU to staples and try another I'll inspect the best to my ability the soldering just strange it would be on two separate risers.

Also both PSUs stated they had short circuit protection is that to prevent the PSU from frying or to prevent the components from frying? I know the Kingwin is a good quality PSU I hae there lazer series 80+ platinum in my desktop PC and when I tested some cards it was able to handle 200+ watts over spec for 18 days straight (it was actually dual rated platinum at 550w gold or silver I forget at 650w)

How should I utilize the PSUs? What my plan was and I was enacting while scaling up was: PSU # 1: 750w - 2 GPUs, Mobo, SSD which undervolted the whole system runs 630-640watts according to my kill-a-watt so that's great. Then I got the Kingwin with the intention to power 4 GPUs and 4 risers its 1k watts which I know I could have them running around 800-900 watts with undervolting the cards.

I will contact Cablesaurus and see if they have any advice. Thanks again

Short circuiting? Bad quality power supply?

cheap/old PSUs need a minimum load for 3.3/5v rails ...

besides that your second PSU is used to power the second GPU but what powers your powered riser? the 1st or the 2nd PSU?

short circuit on the riser ? i( checked mine and the soldering on the wires on the PCB is not always perfect ...)
if it's a nice PSU there would be protection against that.

Sorry to keep posting but also I connected a kill-a-what each time and it read nothing how is that possible they were both turned on

I have a really good nose (lol) I noticed of the riser card the x1 pci-e portion smells very strongly of burnt plastic. The PSU itself smells the same way. The GPU had a extremely faint or possibly nonexistent burnt smell. What could this mean and what do I have to do to run 2 GPUs for a 6 card rig?