MAHA MPJ Series, Original Operating Instructions

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52
BA550001-en
11.2 Electrohydraulic pit jacks
Malfunction Possible cause Remedy
Pit jack does not respond no electricity
Check mains connection
Check fuses in the
control box
Piston rod does not
extend
Pump / motor defective
Check pump for running
noises
Control defective
Check connections in the
control box (push-button)
Replace control box
(customer service)
Piston rod only extends
without load
Potentiometer defective
or position incorrect
Check the position of the
potentiometer
Check connections in the
switch box
Replace potentiometer
(customer service)
Air in the system
Loosen the bleed screw
(under the head plate)
and press the open
button for approx. 1 min
Hydraulic valve / block
defective (rare)
Remove the cover, turn
the potentiometer all the
way to the right, press the
up button and check the
valve coil for magnetism
using a metal object.
Turn the potentiometer to
the left and check
whether the magnetism
becomes stronger. If not,
check connections and
control unit, replace valve
coil if necessary
Replace hydraulic block
(customer service)
Potentiometer shows no
effect (check with load)
Potentiometer defective
Replace potentiometer
(customer service)
Amplifier card defective
Replace amplifier card
(customer service)