Z820 USB 3 issue

[PatBranch]

I have a jbod enclosure with 7 disks connected to one of the rear usb ports and a usb hub connected to the other. When I plug it/turn it on in after startup, they all show up.

When I connect a card reader and a sata-usb3 cables to the front ports, the hdds in the jbod disappear as well as the card reader/sata-usb ssd. I've tried rolling back the Texas Instruments driver and installing an older one, but this seems like a power issue. Has anyone had this happen?

[DGroves]

there can be numerous causes, you need to try to narrow down the possible cause

the usb ports on the z820 go to several usb hubs hubs that are contained in the usb chip(s) that are onboard

a example would be two usb ports per hub, so as a test try moving the jbod case to each usb port and see if the problem persists across each hub if so then the motherboard usb is most likely good

now, connect the jbod enclosure and try another usb card that has a different usb chip (the z820 has a onboard TI USB chip)

and note the result

the next thing to check other than hardware is drive lettering,......tor this test remove all external usb devices boot the system and connect the card reader, note which drive letters it takes now connec the JBOD enclosure it should skip the drive letters in use by the reader and grab free drive letters if so power off and restart with card reader and JBOD connected, do all letters still appear? if not the jbod enclosure is most likely at fault in that it does not like the usb card you are using

HINT:   the z820 has onboard usb 2.0 headers on the motherboard,....connect the card reader to the onboard usb header and see if this works as it will remove the need for a external plugin usb card