External USB Drive no longer seen by bus

My USB raid is no longer seen on by my macbook.

Not even on the bus or in disk utility.

I bought another of the same 2.5 raid enclosure to see if that was the issue, but it has the same problem.

Then a bought a different brand of enclosure. Same problem.

Bought new HDs, none of them work in any enclosure.

They all spin up and power up and you can hear the disks being read but nothing appears.

When I use the disks with a non-raid enclosure they appear.

It's really bizarre and I haven't seen an issue like it before.

Would love any adice.

2014 Macbook Pro.

Previously running Yosemite, then the Yosemite beta, now the El Capitan beta.