I have a Robin 4102 Earth Tester which tests the impedance of a ground earth connection, it comes with two earth spikes which are connected at 5 and 10 metres plus the earth rod under test, the meter is an analogue type.
This unit was donated to the radio club that I belong to. However, the batteries were all corroded and needed a new battery connection. I have cleaned up the battery case, some of the PCB was also corroded so I have replaced the battery connector and resoldered the dry joints etc.
The unit does a battery test OK but just sits in mid ish position when switched to measure, I have tried a decade box across it but it just sits in the same position.
Does anyone have any instructions, service manual or just the method of testing one of these earth testers.