What causes a bill validator to not pull bills into a vending machine?

When a replacement bill validator that is programmed and set-up correctly does not attempt to pull in bills but purchases can be made using coins, the failure is usually due to the coin changer. If the vending machine in also not accepting coins, then go directly to the owner’s manual of the machine to resolve the problem.

Newer bill validators have a LED that indicates the status of the unit. By matching the number of blinks to the trouble codes, you or your technician will be able to easily determine why bills are not being accepted. Review the owner’s manual of the host machine and the manual for the bill validator to confirm both are set programmed properly. If the replacement bill validator has dip switches, the configuration should match the previously working unit.

Disclaimer: the tips below assume the validator and control board are programmed correctly.

The harnessing for the validator and coin changer should be inspected to confirm no wires are broken or any pins are pushed out of a connector.

If the bill validator trouble code indicates “Disabled from VMC”, then the issue is likely due to the coin changer or possibly the control board. The issue is usually the coin changer.

First, look to see that all the coin tubes in the changer are full. If not, fill the tubes and retest.

Next, verify that each of the coin tubes pays out a coin. If any fail, correct the problem and retest.

In the event one of the coin level sensors in the coin changer is not working, the validator may not be enabled even if the coin tubes are filled. This is a very common error.

The next step is to install a replacement coin changer with filled coin tubes. If this does not resolve the issue, then install the bill validator in a different vending machine or test with a standalone tester. If the bill validator accepts bills in a different machine, then the next step is to test the control board of the machine.

If your machine is a single price machine, there is no control board so focus on the coin changer or harnessing.