You have two different issues here. The Rowe 4900 will not display anything when the door is closed if no money is inserted first. This is normal, meaning no one will be able to check a price without first putting money in. With the door open, which puts it in the service mode, you can see the current price by pressing the selection. This is because you have the ability to change a price when in the service mode.
The bill validator not working can be a number of things. First, you must have 15 coins in each coin tube so the machine knows it can make change. What model of bill acceptor do you have? Do you hear the transport motor run when a bill is inserted?
Open the door and look at the outside credit display for any error codes. Write them down and post them here. Keep in mind that if an error is displayed, there will be information in the two sections of the credit display. After viewing an error, press "Enter" on the keypad to view the next error and continue until all errors are recorded. After writing all the errors down, you can erase them by pressing the red button on the coin payout module above the coin mech on the top of the sliding panel.
Now pull out the door interlock switch at the lower right to simulate being in the vend mode. What light(s) do you see on your bill validator and what states are they in now? Try to insert a bill and what do the light(s) do on the validator?
