SRVO-072: PMAL alarm (pulse coder fault)
The controller suspects the encoder itself has failed.
What it means
The controller suspects the encoder itself has failed. Short list, expensive answer: on these motors the encoder isn't separately serviceable in the field, so the fix is encoder/motor replacement - unless it's a phantom riding on a communication alarm.
Common causes
Ranked by what technicians most often find, most likely first.
- Phantom alongside SRVO-068 DTERR / 069 CRCERR / 070 STBERR - if those are in the history, they're the real fault.
- Genuine pulse coder failure.
How to fix it
- Check the alarm history for the 068/069/070 communication trio first; if present, work those remedies before condemning hardware.
- Otherwise replace the pulse coder (motor), then perform mastering. Power-cycle to clear.