ASIC Cube Block Erupter help

[iameric]

I purchased two Erupter Cubes, one powered up no problem and is connected to the mining pool without any issues.

The second Erupter Cube will not power on for more than a second.  To verify it's not the PSU I am disconnecting the PCI Express power pins from the working Erupter and plugging them into the not working Erupter.

When I plug one in the SB Power light turns on and will stay on, when I plug in the second PCI power power pin the unit powers on or just a second, the fan spins up then the unit turns off.

Any ideas as to what could be causing this?  Do I need to reseat everything or what?

Edit: the fan for the non working miner will power up without the fuse plugged in, but as soon as I plug that fuse in it shuts off.

[hostmaster]

it seems to me you need newer PSU or voltage issue.

[DocGonzzo]

I am having an issue where my Cube starts up and runs well, clocked on high, for about 8-12 minutes and then seems to switch to my backup pool (which is the same as primary) but the speed drops down to zero and then ramps back up again. I am using BFGMiner with the --http-port function on a Beagle Bone Black that is also mining a few USB sticks (Antminer and Red Fury) as well as a Jally. I have tried switching operating systems, OSX and Win and even used Slush's proxy, but the effect seems to be the same. The average hash speed of the Cube comes to just over 20GHS with the speed up and slow down occurring frequently about every 10 minutes. I'm using a Corsair CX500 to power it, and that is the only thing the PSU is running. Any ideas?