It would be worth testing your PRAM battery, and if it's out of voltage spec, replacing it. Even if it doesn't fix the problem, it will be a necessity to have whenever you get it fully functional. I've got the same model as you, that's also dead. The power LED lights up, but nothing else comes alive or makes noise when the power button is pushed. I've tried all the troubleshooting steps and have attributed the problem to the PAV board, which I learned is the common failure point on all of these. I thought I had a NOS replacement PAV board purchased on ebay, but after 3 weeks, the seller never shipped, and ebay had to refund my money. I'm on the hunt for a working one, but I am more curious about repairing the current failed board.. which is where I can't find any information. I'm following this post in case anyone has any information on the repair of these models.