[ksalisbury]

Hi all,


We have a 1980's era Fanuc/General Numeric control that is randomly throwing an alarm (red led) on the power supply/regulator PN A14b-0076-b001 01. We checked the input ac transformers - incoming power is ok, and we replaced the A14b-0076-b001 01 with a new unit. Unfortunately the alarm still randomly comes up and the machine stops when it happens. It is not obvious to us why. The local support staff we use seem to be clueless on this era fanuc/gn controller but they were happy to quote an upgrade to the controller at $70K. Of course, we do not have schematics to help troubleshoot anything beyond the obvious. Anyone with experience on this old fanuc/general numeric beast have thoughts on where to go next troubleshooting this?

Thanks!

[hrh]

A14B-0076-B001 is the "INPUT UNIT" which controls the ON/OFF sequence and door interlocks.

The red LED on this unit is an indication of the PSU fault or the PSU is going into alarm because of an external +24VDC short-circuit or problem with the input power.

Check if the 3-phase input is ok.

Check for damaged cables or shavings on limit switches.

Damaged encoder cables or short-circuit inside encoder connectors for axes.

You can send it to me for repair. (not feasible because you may purchase a unit in the US for +- USD500.00)

Replace or repair the PSU...