AP 123 Entire Shelf not working

[Darrell Lindsey]

I have an AP 123 machine that has it's top shelf not working (Gives the message invalid selection). I have swapped the shelves and it works on others. (The motor tests come back ok.) I am guessing a bad harness? (or maybe a board?) Any suggestions on troubleshooting. I have another machine that has two motors out on the top shelf as well. I replaced them, but they still show as invalid selection when chosen. The motor test fails on this one.

Thanks

Darrell Lindsey

KJM Vending, San Antonio, TX

[AngryChris]

If the shelf works when you swap it, then it's definitely not the shelf or the motors on it (although there could be motor problems but not relevant to this problem).  If test vending does not work, i would try reprogramming prices and see if it fixes it... if not, then you have to check the shelf harness.

On the second machine, it's probably bad motors.

[AZVendor]

The most common failure with 123s is the motor harness that goes from the logic board up to an adhesive cable clamp on the top of the cabinet and then back down to the first shelf.  The clamp will lose adhesion and come loose so the harness is left to hang behind the swing-out panel and over the power supply.  All of that weight on the moving swing-out panel eventually breaks a wire somewhere in that harness.  The fix is to splice a new wire to bypass the questionable wire from just off the logic board to just above the top shelf connector. In your case it will be the A wire that needs to be bypassed.  To confirm this you can ohm out the A wire from the logic board connector to the top shelf connector and no continuity is the confirmation.