My NF is acting pretty wonky. Some games play fine, some play fine for a while but then wig out, and I can't find a trigger that causes it. Symptoms are general ridiculousness. Music firing that doesn't belong. Multiball starting when balls weren't locked. Extra balls being launched (but not multiball). Occasional firing of magnets when ball is not in accelerator. Occasionally magnets NOT firing when ball IS in accelerator. I can't figure it out.

5v is almost bang on at 4.99V. Magnets all read at 5 ohm resistance (pinball ninja said one possible issue is magnets burn out and start causing silliness when they short). Switch / solenoid / lamp / flasher tests all seem to be ok.

Anyone seen anything like this and figured it out?

Reseated them and still had crazyness, but did get the top half of my backbox GI in the process (that ribbon cable was loose).
Tried without daughterboard in case it was doing something, had insane-o williams reset issue.
Put daughterboard back, and pressed really really hard on all ribbon cables and played 10ish games without issue.

Looking like it will be ribbon cables. Will have to play for a while more tomorrow to be sure.

Do they fray on the inside? Should I actually replace them? Is there a chance the connectors are bad and would need replacing? Visually, they all look ok.

Thanks!

ok, will do, thanks!

I've replaced the ribbon cables with a new set, they are definitely much more snug, but it's still wonking out sometimes. There is no battery corrosion on the board. I just replaced the battery pack with NVRam, and the behaviour before and after is the same, so I can rule RAM out (if that was ever a potential cause). I have the daughterboard for the power, so power should be clean. What else might cause this? Could a corrupt rom cause it to act up sometimes, but not others? Maybe conditional to a certain sequence of actions on the table or something?

Just did the factory reset. It's still acting up. Played a couple games, it launched an extra ball into play for no reason, it started modes that shouldn't have started, started a multiball on the 2nd ball lock, and is playing the 'game over' music sometimes during the game. Crazycakes.

Switch tests seemed ok in past. I'll try reseating, I have a chip puller, and I'll try to find some way to track voltage vs game wigging out. I have a usb scope and software. The trick will be that I have to be playing, recognizing that something wrong just happened, and watching the scope.

I'll do this stuff this week and hope that the reseating fixes things

Thanks!

Terry was right here. All it took was to reseat the chips, including the asic. Good as new. Cheap fix!