Hi, A local optical store, who cut their own lenses, brought in a WECO CNC-90. It will do it's self test when switched on, however, it won't go into Trace mode (No LED) when told to. Does anyone know if it is necessary to have all units connected in order for the FormTracer to run, via 9pin RS232? Also, would anyone have a service manual, as well as a User Manual for this unit, please, as we have not repaired them before. Thank you.