We had the same problem at our RJ3 System, you can reset this problem by below procedure...
1. Go to...System Variable...$MCR
2. Then, reset Axis BZAL ALRAM by $SPC RESET= make it TRUE to FALSE (Check Vice versa)
Then,Switch off & on the panel.
Then, you can move robot by this.
then reset SPC_PCA Alarm & Remaster that Axis.
Note- 1.While you are doing this SPC_RESET to TRUE to FALSE (o to 1)... it will be just flick for a moment, you need to make it TRUE to
FALSE (o to 1) & Then,Switch off & on.
2. By this you can move your robot only,but,check for what was happened in actual for the Axis? ***As in our case the motor
Pulsecoder connector was broken.
***Make sure to you need to Reteach the all programme(s) of this robot.