My 1987 KM3P has been a workhorse in my small home shop for the past 14 years, but recently it has been having an issue with the Randtronics servo amplifier not powering on correctly; On the Fault Logic Board, the BIE fault LED is on (see photo).

In the owner's manual (section 5.5.7) it says the cause is: "The bias error indication operates if the sum of the plus and minus 12v supplies falls below 22 volts. Peak output current on each bias supply is approximately 2 amperes. However, if either supply is overloaded, it decreases significantly because of the holdback capability. Also, the plus supply tracks the minus supply. The most common bias error fault occurs because one of the supplies is shorted to ground"
The corrective action is: The drive should be reset and retried after external ±12 volt bias loads are removed".

How/where do I locate these ±12 volt bias loads ???

Thanks in advance,
-Mark