CHAUVIN ARNOUX CA 6411 Ground Tester - Repair

[2X]

Hello,
I have the “CHAUVIN ARNOUX CA 6411 Ground Tester” and when the jaws are closed it shows that are opened and also when jaws are closed, I am hearing a noise tic tic… like a relay open and closes periodically. Ι can’t open the jaws to see what is inside… does anyone open these jaws?

Also, I made a schematic from the PCB that the connectors of the Jaws are connected but I didn’t find something and I replace all the chips with brand new except from these two (same) in the yellow circles where I can’t find a datasheet (Image 5). Any ideas for troubleshooting?

[2X]

At the attached files are all the datasheets that I found.