you can test the head by itself to make sure it is working, and at the same time establish which bills it will accept.
very easy test, remove the head from the transport, disconnect the plug on the left side, disconnect the two on the left side. Now, flip the unit over and observe the switches, there are two banks of switches, one has ten, the other has 6, we will use the bank with 6 , flip the number 6 opposite of where it is, we will use the machine power supply to apply power to the head, now insert the white power plug into the head, observe the two red LEDS are on (directly above the plug) , now flip switch 6 back, the unit will cycle briefly, you can now insert bills into the unit, if it works, then it will take the bill in and spit them out the back, you can do this all day long as long as you do not interrupt the power, if so, then just start over. if it doesn't work, then your head or power supply are bad, usually if the red LEDS are on it means the unit is getting power.
Hope this helps
Jim
I do have 200 heads for sale.