Hello, and thank you for the valuable resource.

So far, I have browsed quite a bit in trying to figure out what's up with this machine. It's not mine, it's my grandfathers machine. I'd love to fix it for him, he'd be thrilled. As would the rest of the family, as everyone loves playing his Pachi machine (though, everyone calls it a slot machine, which prior to investigating this, I did too.. And I certainly will not do that anymore now that I actually know what it is)

So what's happening is the thing was definitely absolutely terribly 100% jammed up. Lots of coins stuck in there, not a very fun time clearing out all of those coins, though glad the motor didn't burn out. Cleared it out and all seemed well... Until it went to spit coins out. It'll usually spit out 2 coins then immediately E1 and stop responding. Need to reset it when it does this. It does the same thing when manually pushing the red button inside to spit out coins directly, but I can usually hit the yellow button (reverse the hopper motor) and it'll let me hit the red button again after a few seconds... but after 2 or 3 times, i have to do a full reset for it to start responding again.

While this seems like a clear-cut hopper sensor problem (to me at least.. Though I keep seeing E1 can be RAM on most machines.. Which, to be honest, I have no clue how to identify the manufacturer.. Everything is written in kanji), the real issue is the amount of variations between machines.. This is NOT the machine I'm working on, but it does appear to be the exact same model:
https://www.youtube.com/watch?v=THs4nCTxFV8

How would I know whether this is optical, mechanical, etc? I fix plenty of electronics and mechanical stuff, but this is my grandfathers machine, and I really don't want to pull the hopper apart and not be able to fix it or put it back together. I'd love to know what I'm getting into before I start actually unscrewing and taking stuff apart, so if anyone can possibly give me a heads up on whether I should expect mechanical or optical and if there are any snags a Pachi newbie should watch out for in taking his first hopper apart, it'd be greatly appreciated.