I'm trying to set up an n64, but I'm encountering some strange issues. I have 4 games cartridges handy to test with, Mario 64 rumble version (Japan), J League Live 64 (Japan), Rogue Squadron (USA), Episode 1 Racer (USA) I have 2 regular jumper packs to test with, and 1 expansion pack. The issue I am encountering is that some games don't boot at all with jumper or expansion (Mario and J League), and the other two have pretty severe graphical glitching with just a jumper pack installed, and seem to run mostly okay with some possible glitching when I have the expansion pack inserted. I assumed this meant something was wrong with my motherboard, so I got a replacement motherboard for a reasonable price. I test with it, and I am getting the exact same issues. It seems surprising to me that I have bad luck with all 4 game packs, is it the most likely cause? All were obtained from separate sellers online. Other common factors are my power supply and video cable, and television. I used a cheap multimeter to test the voltage on the PSU. The two 3.3v pins tested around 3.4v, and the 12v pin came in a little under 11v. I know it's probably not an exact thing, but does this indicate the PSU may be the culprit? I will also lend some cartridges to a family friend who has an N64 for testing, but it will be a little while before I see him, so in the mean time, I wonder if anyone here has ideas for troubleshooting.