Maybe I'm dumb, but is there an easy way to tell which device is which?

In BFGminer, I have the list of 6 devices, MLD 0 - 5. Occasionally I'll get a message of "MLD 5: ASIC has stopped hashing, attempting to restart".

I know it's because of power issues.

But I can't seem to isolate the problem one.

I've tried to disable it through the "manage devices" menu, but all devices keep flashing leds.

Is there some trick to figure it out?