Quote from: daemonic on September 08, 2012, 01:20:57 PM

I would just like to again thank everyone for their hard work on everything getting us to this point. After following ebereon's little guide ive tuned my cairnsmore1's to run at a nice level;

This is powered directly from an old ATX psu (200W Max on 12V @ 8A (which should surely be 12V*8A=96W??))

However i have a small issue where I occasionally lose all 4 com ports (Win 7 64bit directly connected to pc) at random intervals. I have to disconnect the usb and power cycle the cairnsmore1's then reconnect the usb to get them back. The idea is to move these cairnsmore1 to my datacentre, to run off of one of my linux machines, so this is not an ideal situation if it continues to happen.

Ive changed the usb cable which seems to have helped somewhat (as you can see 20 hours from the image above), and ive ordered one of those recommended 35 port usb hubs to help also, is there anything else i can do? (I guess worst case i can remove the 5v from the usb cable and hook the atx up to the remote power bar).

We have seen USB ports be lost when something else is plugged in like a memory stick. We also think that sometimes a surge of current taken from the USB also causes a disconnect and a power USB hub seems to help here. It might be the plugging in of something else is actually a power problem. We have seen some machines (particularly laptops) prone to this and it sort of suggests maybe a dip on a shared internal power rail in the laptops might be a cause. Short of analysing every combo out there it's going to be very hard to totally identify this issue and our preference is to reduce the dependency on USB if not remove it totally with our rack controller concept.

If anyone has seen a benefit if cutting 5V on the USB wire as input to their CM1 we would like to know. We have been short on people to look at our test boards properly where we have done effective the same at board level so any data on the effect would be useful to us. We should be back to full staffing strength later this week for the first time in 10 weeks but there is something of a backlog to catch up on so it will still be a bit slow here for a few weeks.