I have a 6555 that has being dropping out of the network intermittently. When it stops working the amber light at the RJ45 at the machine goes off, the green light is on. I have plugged the network cable from the machine to a computer and the network is working properly. I reseated all plugs on the controller board, reset network settings, and did a reset on the machine with no luck. It will start working randomly just sitting there. I believe the controller board (JC92-01941D) is probably defective but it is expensive and hard to get. It is on backorder at Collins. Has anyone tried to connect an external print server to this machine? I tried an HP Jetdirect 310x but it did not work. 