I got my Twin Fami in the mail today to start restoring. When you turn it on it shows a blue screen, so I thought it might be memory issues. I tested the 7805 and it's actually not regulating. I had 9v in, ~8.3-9v out! :-\
I tested it on 7.5v and it was outputting near 8v.
I am replacing it with a switching regulator, but I'm hoping the IC's didn't fry. What is the maximum safe voltage the chips can take?
That's not a 7805, it's a 2SB941 transistor. The Twin Famicom has very different power circuitry compared to a regular Famicom since the PSU/AV board has to supply power to both the Famicom board and disk drive, and I found that if you go above 7.5V you run the risk of overheating or overvolting components. I once made the stupid mistake of feeding 9V to mine, and after about an hour it blew an op-amp chip in the disk drive.