I've had an ACA1233n for a while now. It's worked, then caused me problems, then works again. I don't keep my 1200 up and running all the time, so I've not actually got to use it that much over the past year or so.
I set everything up yesterday. Everything was working fine. I went to install EasyNet Pro, and then everything started to go wrong.
So I pulled everything off. The 1200 boots up fine as stock. I put the ACA1233n back on. All I get is a black screen, take it off again. The 1200 works fine. I've tried the moving the ACA1233n back 1-2mm etc, but that does help, and besides, it had been working anyways.
I've stripped the whole 1200 down now, and come to notice that the parts E123C and E125C are still there on my v1B board.
I bought it brand new, and have used it very little, for short bursts (an hour or so) at a time, a few days at a time. With months of the 1200 just sat on a shelf.
I've purchased a second 1200, the ACA1233n doesn't work on it either. I've got a modern PSU, so it shouldn't be the problem.
Hopefully this can be solved, and it's still under warranty? Since, I've actually hardly ever used it.