Fanuc Control

I have a customer who has a cnc router, sometimes with errors an faults- is there any way to connect and troubleshoot this fanuc controller- software and connecting cable-

You have a GE Fanuc CNC controller and three Alpha series amps. I can't read the model of CNC controller. GE and Fanuc dissolved their joint venture at the end of 2010, so your unit predates that. Please supply the info from the controller nameplate. Do the faults you're seeing show up on the 7-segment display on the amps or on the display unit of the CNC? You can do a lot of troubleshooting from the fault codes that show on the display unit. Do you have any of the manuals for the system? The controller's maintenance manual will have list of the error codes and troubleshooting procedures. If you can provide the model number, I can probably find the publication number of the correct maintenance manual and possibly even come up with a pdf copy.

Probably a 15M or so control.
Look at the top of the HMI screen.
What are the faults? Faults that start with (SV....) 414,300 etc, or just number faults like 1021, or 2090, with a description.
You can view the ladder from the screen.
System,hardkey > pmc ladder, softkey.
Make sure you have a backup of everything before you start button pushing.
See that slot on the main board, you may be able to use an SRAM card to back that up.