Wba-12-ss making grinding noise not fully accepting bills

[leydet4]

My wba 12 ss stopped accepting bills. I have been through all the settings to check to be sure dollars is the currency, all the dip switches are off. Have seated and reseated all parts of the set up. When it is seatted and runs through it's start up it sounds ok for a few seconds then does a weird back and forth noise about 7 times. None of my other machines do this. Any help?

[Amechanic]

Have you taken the bill acceptor out and opened the back cover and the top on the bill head to look for maybe apiece of bill jammed inside? You could also wipe off the optics in the bill head.

[Sunrise Side]

Swap the head from another machine to find if the head is the problem or the transport is the issue.