What is wrong with my DN?

[Timekeeper719]

I have an older Dixie Narco cans only 2 deep machine. It has 6 selections with the first two tied together. Its branding is Coke. It’s a single price machine. I don’t know what model and the name plate is so worn that it’s illegible. 
If a customer puts a dollar in the bill acceptor or coins in the mech, the machine immediately drops either Sprite or Doctor Pepper. It only drops once payment is made. It doesn’t do it every time either. Nor is it consistent. Sometimes Sprite, sometimes Dr Pepper. I can’t figure out what’s going on. Does anyone here know what’s going on?

[orsd]

The motor brakes on those columns is gummed up and the motor is coasting past the notch for the switches.

The brake is a little brass tab on the motors that you can push up, it should come right back down. If it’s sticking in the up  position or lags a bit coming down it’s gummed up and must be cleaned. Try unplugging the machine and spraying some 91% isopropyl alcohol on the area to clean the brake. Let dry completely, plug machine back in, and test.

Edited June 15 by orsd

[Timekeeper719]

I will give this a shot, thank you!

[AZVendor]

It's a DN276.

[Vendo Mike]

If the motors aren't home, the unit should not accept cash as it's still stuck in a vend sequence.  I would be looking for stuck selection switch(s).  Does this unit have wide and narrow columns?  When counting columns, you should count the wide columns first and then go right to left in the cab.  I'm curious if Sprite and DP are sharing button #1.

[AngryChris]

I have a 501 that had a selection button sticking in one corner.  I solved it by using clear packing tape that prevented someone from pressing the button into the side that kept getting stuck.  It might not be your problem though.