Multiple Vendo V721 MDB failures

[Chrisagu28]

Hey everybody,

I have been searching for days trying to figure this out but I simply have hit a dead end so now I am looking for advice. I will try to give the history and troubleshooting I did thus far. 

I have 4 Vendo V721 machines I manage and take care of in my work. We use a ITC system for the card reader. We don’t use cash or coins in the machines. Any issues I have had with the machines over the years, I have been able to solve with the service manual but this new issue has me stumped. 

Recently three of the four machines start having the same issue up all around the same time. It is intermittent were they will just work when they want which is all about of 20 mins then present the issue again. The problem is, the Card readers are showing “SOLD OUT” yet the vending machine is still fully functional with the exception of a error once I enter service mode. It states “CARD READER ERROR -NO COMMUNICATION” 

The service manual for the ITC card reader states - An “Out of Stock” message is displayed if the vending machine is out of stock or the CAD is unable to vend due to an MDB system failure

So I started troubleshooting the machine to looking at sensors and the mechanical side. I didn’t see anything that would make the VCM disable the MDB. I am able to successfully vend via test mode and when the machine is working, it works vends with no issue. I swapped the main boards from the good working one and a bad machine, the issue followed the bad machine board. The good machine board got the other machine working with no issue. 

I feel I am either left with ordering 3 main boards or investing in a MDB tool to determine what output is being sent out from the VCM to help in troubleshooting the issue further. Am I over looking something in this issue? 

Thank for your time and patient in reading all this. 

[lacanteen]

You probably need the newest firmware for the boards it usually comes as a flash chip or EPROM

[AZVendor]

Or your cell signal that they use just went weak due to poor cell service. 

[Cozzmo]

I Installed a SEED cantaloupe cashless unit on a 721 and had to use one of their supplied ‘inline filter’ cables to get it to work at all. Wouldn’t talk to the VMC even after updating to 12.1RV35 EPROM. They told me some machines no issue some machines it is an issue. Not sure why but immediately after installing the filter cable it worked. Maybe something similar is required if it’s not one of the other suggestions.