I have two Facit N4000 paper puncher on my hands. One of them has some strange behavious that I don't know how to fix. It appears that it can't punch the paper in a smooth way -- it stop a second in punching process from time to time. And the data on the paper is wrong! Can anybody tell me how to troubleshooting this paper puncher?

Thanks in advance.

You have an over punch, the holes blend into each other?
This is due to a badly worn exit guide, block and pins or a motor mount, along with the requirment to calibrate.