When you are visiting your locations everyday you must keep in mind that always properly open the machines and checks the coin mechanism top part flap 
just partially open it and also check quickly the coin pathway to see if there are coins that are jammed.
Most of the problems are the ones that are used most. And while you are servicing the machine, always checks the plug sockets and be sure that everything is tightly snug and fit.
Also check the evaporator if it is clean and not dirty, you should use a wet cloth or towel to remove any dirt that have accumulated.
I’m servicing more than 100 machines and by experience it is just the coin mech and evaporator that needs to be checked all the time and also the bill validator has to be re programmed from time to time to accept new bills.
Maintenance is a very easy job. Your work is mostly visit, smile, collect, refill, leave scenarios.
