if you really want to fix it open it and reflow the solder on the power supply connector that connects to the main board fixes it 100% of the time

These old threads are still helping folks out. I'm going to try the "paper shim" fix.

Hmm I only had one N64 sent to me for re-setting issues. It was due to muck buildup inside the reset button and the top plastic. Once I torn town cleaned and re-built the console ran fine. The oddity about this paper shim fix to me is why it's needed. I have a few times tested work in progress boards without the case.

With that being said...if a game resets with a clean reset button, that tells me the pins on the board has corrosion. Which can be cleaned with a wire brush.

Replace the power supply. Occasionally the OEM power supply can go bad. The console resetting itself is a sign of a dying PSU because the CPU is not getting proper voltage on the 3.3V output. The N64 console should still be fine once you give it a new PSU brick.

One of my old N64s started doing this. I checked the controller port with a multimeter while running Banjo Kazooie as a stress test. The voltage is supposed to be 3.3v but it started at 3.11v at boot and slowly dropped from there the longer the console stayed running. Around the time it dropped to 2.92v, the console spontaneously reset itself and would continue to do so until I powered it off.

I bought a used OEM power supply from GameXChange and that fixed the console. 3.34v steady with the secondhand oem supply. I haven't tried the new replacement supplies but they offer 3rd party new replacements as well. As long as they output stable 12v and 3.3v signals, they should be good.

Always best to test 3rd party supplies with a meter first to make sure it's not putting out too much juice. I've seen "9v" Yobo NES/SNES bricks putting out a whopping 15v out of the box. Yikes!

EDIT: Holy shit this thread is old. Still though, check the voltage at the controller port (1st and third pin) while running if you have access to a multimeter. If it's well below 3.3v, it's probably a bad supply. Never heard of fixing the console with paper shims or tape and stuff. The solutions you guys come up with is grand.

Excellent information Kosmic! I think my psu has this issue. Didn't even think of checking the voltages through the controller ports under load. You think replacing the caps is all that's needed on these psu's that no longer have enough juice?