Don't know the thead is still alive.. Anyways..
Man the problem you described was exactly what I have, but,
Let's just say I bought a Xperia Play R800i via ebay, knowing the damn thing would come with situations which the seller said it did (This is true, believe me - think it as you selling me your phone in that state).
Returning.. the issue was the screen, black as you described, just adding a thing, I'm new to SE software, not android and it mentioned "A blackscreen state when returning to standybe screen".
What you think? software problem, obvious!!
Looked for support.. updating roms and not clear how to use the flashtool (just downloaded it
but.. the damn problem is when it turns on or not and when it happens the same in standby mode..
Now, I have the phone due tree days, me trying to understand with a fellow collegue of mine at work..
I suspect that, there is a updating problem that can "damage" the screen (doubt its my cenario now) and pain in ... to find a way to do a clean install to verify that, thinking: "there is a chance to have to do this blindly? Oh yeah, IT IS A BLACKSCREEN STATE PROBLEM!!)
Anyways, I'm not asking for real help, just ideas but let me tell you this (first poster specially), today I've somehow concluded ( not real sure
) that the phone appear to show up the screen after I try to turn it on after i slidded up/down the pad, so my first guess would be the problem, the tning is that in my way, not allways it works..
The phone looks damn awesome, and it's on right now
but i suspect that if I slide the platform within "sleep" (the black android suspension screen to be clearer) it won't woke up.. Althoug not permantly.. Yeah, I have to retrieve the battery and so, blah, blah...
What I mean is that the screen its not "dead", and I doubt the Clean install would work, but you're the first Ones mentioning the most similar as my case can be..
Last thoughts, I could sent it to repair, believe me, no prob (not using for instance), but I would like to know what is happening since I would like it reliable