Total corrosion.
DC-DC 24V/12V dual to DC-DC 18-36V/15V (MIW5037) - dual.
Non correct circuit protection (1N4148 -2).
10R/2W, 4700uF/35V, 220uF/16V, wireup 1 line, terminals -2.
Replacing all screws.
Calibration: 4mA => 0, 20mA => 999.