Coinco model S75-9800A Problems

[bammbamm401]

I am a newbe to the soda vending macine club and I am hoping someone can help me.  I recently bought a Dixie Narco model 168/99-6 Pepsi machine and I am having problems with the coin mechanism.  The Coinco Model S75-9811A mechanism will only dispense soda when I put in a $1.75.  From reading the labels inside, it is suppose to be a max of $ .75.  I tried setting the price to .25 (thanks to the manuals on SMC) and it still only dispenses at the $1.75.  Anyone have any ideas how to fix this?

Thanks. 
Bill