A 3100 is a hopper error - generally meaning an extra coin has been paid.
From a fundamentals perspective - when it comes time to pay out the slot turns on power to the hopper, a coin passes by the hopper optic and when the prescribed number of coins is paid the power is cut. However momentum carries the hopper wheel to keep moving, so a hopper brake kicks in and stops the wheel from spinning.
The error is resolved by pulling the hopper - looking at the back of it - the hopper brake - is pushed out by a solenoid when the hopper is running and when its time to stop there is a small spring that pulls it back and "brakes" the hopper. Thus stopping it from paying out more coins. When you get these errors its usually because the spring is broken or missing. If its missing or broke replace the spring. The spring from a bic pen can be used in a pinch.
If the spring looks to be there and doing its job - the error can also be caused by a loose hopper after transport or other vibration - reseating the hopper will probably clear this.
The 41, 42, 43 are reel tilt errors and they correspond to each of the reels.
Here is a video, courtesy of SlotMachines Ltd. on how to clear a reel tilt
https://youtu.be/dTpkhJB5SBMLet us know how you make out.