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.
Found in a 90s Popular Electronics, this circuit is interspersed between the filter and the...
This circuit is from an 80's documentation. The integrated circuit is from the time and the...
This circuit was found in a 80s American documentation. The zener diodes determine the points of...