I have a Dixie Narco 501T/280-7 vending machine. The machine is cooling well and when I press the switch for each individual motor I can get a pop to dispense. However, when I put money into the machine, it automatically goes to the change return. Sometimes, when I plug in the coin mech, it makes a loud buzzing noise. Other times, it makes no sound at all. Although we are still not positive the coin mechanism is the problem, do you have any idea which coin mechanisms are compatible with this vending machine? The one currently in it is a Mars 6200. Is this the same one I should get or is there an upgraded one I should be looking at? I do not have a manual for the vending machine or the coin mech. Also, do you think the problem is something other than the coin mech? Thanks!