Olympus MJU 1 dis- and reassembly + issues I fixed in description

Different issues I fixed:
For all my MJU repairs I used spare parts from a broken MJU
Camera 1: On this one, the film would wind but the camera thought it didn't. I swapped the part with the motor for extending the lens (10:41), because that's where the gear sits that senses if the film is moving. (And I forgot the gear..)
Camera 2 : The shutter didn't work. The lens did go out but the shutter did do anything and it was stuck there until you close the camera. For that I swapped the entire lens unit (10:18). I don't know if it was the flex cable, which is usually the culprit according to the internet. It looked fine and I didn't bother with opening the shutter up, if I could just swap the entire thing.
Camera 3: It wouldn't wind the film. The culprit was the swinging gear at 4:20. You can either swap the plate that it's on by de-soldering it from the main PCB or swap just the gear without the swing arm, that's what I did.
Camera 4: rewinding didn't work. It was the tiny gear on right side at 3:49. It is attached to a long shaft, which connects to the gears on the topside of the camera.
It also happened once that a camera would only shoot if the back is open (while testing with no film), putting a roll i of film in fixed it
Good Luck!
By the way, the Olympus Ecru is internally almost the same as the MJU. The biggest difference is the flash unit. It's basically a MJU in a weird body and some things like the flash are different because they are at different spots.