Hello, in principle everything is explained in the other post. The position of the DIP switches is also mentioned there. However, older iDRs probably do not have the switches in this position (on the right in slot B).
yes, exactly. This is a NiMh cell, the liquid is corrosive. I would measure the discharge current and also check whether there is a charging voltage at all, this should be at least 3 volts and also measure the charging current