I have an older dixie narco coke machine that vends 5 choices at a fixed price. The model is 300-e and the serial number is 0359-1179as. This plate is on the bottom inside of the machine. I am trying to figure out what year this was made etc to order parts. Everything works/runs great. Just needs a few out of soda lights replaced. I am wondering how to change the fixed price. The label is original on the outside and says 40 cents. It currently is set at 75 cents. I want ot change it to 50. I dont see any switches etc to do this. What am I missing?