Wanted another opinion on this - there's a 27" Thunderbolt Display on eBay, where the seller says it has stopped working in the last week after someone young messed about on his mac - USB and charger work though. Is it likely that this is some bad display settings and potentially a cheap buy, or does it sound like a genuine fault that should be avoided? Iirc, when connected, these displays cannot be turned off, so that would lead me to thinking it is actually broke! Your opinion would be great here! Thanks!