Hi Chello, this may help with your E1 error. Sometimes bent tokens or built up grime will cause an error. Dirty or thinner tokens can jam up the hopper. There may also be a fuse involved (typically on the power supply box). Check fuses with a meter if able rather than just visually. Another item could be a dirty or faulty opto sensor that are on some hoppers. A good cleaning of the hopper is my first step if I don't see an obvious cause.

E-1/ (HE/ HJ) The hopper may be jammed. Turn off and unplug your machine, remove the hopper and take out all the tokens and look for what ever has jammed it. The dial in the bottom should turn freely by hand.

As for the screen try unplugging and reseating the connections if you haven't already. You can also look for bent wire pins at the connecting points. I have not had monitor troubles so I'm not sure about what else to check.