I'm currently looking to buy a used TB display, and during this week I'll be checking one out not far from here. It's three months old, everything seems to be in order formally. What - if any - particular issues should I keep my eyes peeled for when concidering a used TB display? Is there any way to run a diagnostics test to ensure that everything is in shipshape? I'll be bringing my MBA in order to hook it up and test it before I buy it. Any advice would be greatly appreciated!