Gumball machines have been around longer than almost any other type of vending machine. Sought after by collectors and retail businesses alike, they are a charming decor element as well as a source of revenue. The basic design hasn't changed much since their introduction in the early 20th century, so they can be repaired with relative ease with the right parts and technique.
Examine the gumball machine to determine which part is malfunctioning. Gumball machines generally have four parts: the globe that holds the gumballs, the dispensing wheel that releases the gumballs, the coin mechanism that accepts coins and activates the dispensing wheel, and the base that holds the coins.
Check the globe. If the globe needs repair, disassemble it by unscrewing the screw lock at the top with a screwdriver and slide off the nuts, gaskets, and retaining ring that hold it in place. Replacements for any of these parts are available for purchase at a number of vending machine part retailers.
Check the dispensing wheel and brush-off plate. These two parts are located at the base of the globe and shift when a coin is inserted into the coin mechanism to dispense the gumballs. If one of the parts is damaged or malfunctioning, purchase a replacement from a vending machine part retailer.
Check the coin mechanism. The coin mechanism is located in the front of the vending machine, beneath the dispensing wheel, and is the most complicated part of a gumball machine so it can malfunction in a number of different ways. With the globe, dispensing wheel and brush-off plate removed, remove the coin mechanism and test its function by inserting a coin and twisting the vending knob. If a part is stuck, lubricate it with silicone lubricant. If a part is damaged beyond repair, purchase the individual part or an entire new coin mechanism from a vending machine part retailer.
Check the base. Gumball machines have similar internal parts but their bases can be very different from one model to the next. Check to see if any coins are blocking the coin mechanism, dislodge and empty any coins. Replace any part of the base, including the base plate or legs if they are damaged beyond repair.