This configuration with the LM111 was found in your factory manual. The circuit can be implemented with modern operational equivalents. The power supply must be symmetrical.
We found this protection circuit for the power supply in a 1992 documentation. This circuit has...
I found this circuit in a documentation for radio amateurs from 1975. The FET could be the BF245....
Found in an American 80's documentation, this circuit can use common FETs like the BF245 and cover...