2nd PSU cuts out! Please help.

[BulletProof_za]

I have a rig with 3 x R9 280x's ,a MSI 990fxa mobo,600 watt PSU and 750 watt PSU.

The 600 watt runs the Mobo, CPU and a single R9 280x.
The 750 watt runs the other 2 x R9 280x's.
The Rig boots up into BAMT and all the cards are picked up but when it starts mining the 2nd PSU and the 2 x R9 280x's cut out!
The rig works fine with a single R9 280x's on the 750 watt PSU.

Thanks for your help !

!Bullet!

[Wipeout2097]

I have no experience with dual-PSU hacks for mining rigs, but I know a few things about the devices.

Please post web link to the exact brand, model and specs of the PSUs.

What coins are you mining, and at what voltage are the cards?

Do you have (powered) risers and connect them to the proper PSU?

[mac-coin]

I had the same problem

Try plugging your hard drive in the second PSU,  Some PSU need a load on the 5v or 3.3v lines