In dmesg I saw something about possible emi causing the thing to keep shutting down, it would make some sense as the usb runs right past a dc spindle drive on my very messy test bench, I have moved the wire and the problem appears to have gone.
Most new cheap USB cables have no shielding at all, some do have it but not connected to anything, so not much use.
The older ones work perfectly but i am running low on stock !
I use a lot of new ones to power things from USB, so i cut one side and the wires used are pittyful !
