Mamiya 645 1000s mirror problem

I did a quick search and didn't find anything that was the same as my problem. I have a super(broken mirror rest) and a pro, but when I found a good deal on a 1000s I couldn't pass it up.

I bought it off ebay and when I received it, something didn't feel right as I was checking it over so before I loaded a roll I noticed the mirror wont stay up on longer exposures. Purely by sound and sight I noticed that I should be safe down to 1/15 but anything slower the mirror will come back down and crop the image. I put it on bulb, held down the shutter and when i push up on the mirror it will latch and when I release the shutter it will drop. Its as if it doesn't have enough force to latch itself on the top side, or something is in the way and acting like a cushion that wont let it go up far enough. Could it be possible that there is something just worn out? Has anyone else had any issues like this?? I am not opposed to breaking it down a little bit, but I'd rather not. I can work on many things ( bikes, cars, lawnmowers, ect ect.) but cameras are my least favorite. So many springs and tiny screws.

Thanks in advance

p.s. It came with a battery in it but I'll put a fresh battery and try it later.

I was playin with the camera and all of a sudden the mirror wouldn't move up or down and was stuck in the middle. Also the advance wasn't moving so I decided to take that and the plate underneath it off. There is a spring that is lodged between two of the gears so when I get home I'll attempt to get that out and see if I can rig it up with something else for the spring.

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