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so i have two ultra x4 750w modular psus, i was using one with my old gpu rig and one is brand new.

neither of them will stay on only running ants. they power up and stay on for 10-30 seconds. the shut off.


cant turn em back on for a few mins, the it repeats.

they work fine in a PC.

ive googled but cant find a solution... maybe there is something else that needs jumped for it to stay on? maybe it tried to detect a mb??? not sure

have two worthless to me psus i cant run antminers on...

sounds to me like OCP protection triggered, because after 30 sec ants actually start to mine.

i need to figure out a solution, i got ants with no psus, had some psu problems overnight

I have this PSU:

http://www.ultraproducts.com/applications/SearchTools/item-details.asp?EdpNo=1583411&Sku=U12-41563

It ran 2 S1's with no issues for 3+ months @ 825 watts.

Which Ants are trying to run ???

Are you using all 4 pci-e power cables for each PSU and Ant?

I was using two pcie cables per ant s1...

they turn off with one or two ants hooked up.

its like they need some additional signal to stay on

So just try hooking up 4 cables to 1 ant.

Get some better PSUs.  You can get industrial grade server PSU's for like half the cost of new ATX's

https://bitcointalk.org/index.php?topic=622783.0

s1 only have two pcie connectors.

to me, it seems like the problem is they just shutoff because of not detecting a mb...

they shutoff before the ant even starts hashing

Yes I have about half a dozen server psus running. But I already had these ones and dont want them going to waste

It's not a motherboard issue, it's the fundamental design of the PSU. That one is almost definitely an old group regulated design, which means it gets its voltage feedback from both the 12V and 5V rails. It's fine on a motherboard, but when you try to pull no current from the 5V rail and a whole bunch of current from the 12V rail it screws up the sensing circuits. They're called crossloads, and group regulated designs hate them; the rails go out of spec and shut down.

You can probably get them working again by putting a load on the 5V rail (a couple fans might do if they turn on at 5V), but the better solution is just to get a better PSU.

i'll try to hook some fans up to it and see if it works.

this is the exact PSU. I obviously won't be buying anymore, and I wont' be buying anything but server PSUs. I have a bunch of 750w ones running two ands and a couple 500w ones running one ant each. they worked great.

tried putting a load on it with about 6 case fans, it still failed to stay on.

Sounds like a case of POS PSU.

I put a big load on it while running GPUs, max load for days straight. seemed to handle that fine.

it just won't stay on with ants only

probably be an ok PSU in a normal computer