Hitachi IJ UX, Service Manual

Page: 182 / 308

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(2) Fault locating method for the control system/circulation system
(a) When the pump motor and all the solenoid valves are not operated, the multi-power supply
(24 V system) is abnormal.
(b) If the electrical parts (pump motor, solenoid valves, and pressure sensor) are not operated, i,e.,
any case other than above, make the following checks first. When the criterion is satisfied, the
power supply, EZJ126 board, wiring, or connector is abnormal.
Part Check method Criterion
Pump motor (1) Operate the pump
on the “Solenoid
Valve/Pump Test”
screen.
(2) Measure the
voltage at pin
No.5 (wire: red)
20 V DC or more
Solenoid valve (1) Exchange the
solenoid valve
and/or the
connector with
another normal
solenoid valve
and/or connector.
(2) Set the solenoid
value to “Open” on
the “Solenoid
Valve/Pump Test”
screen and check
the sound.
An operation sound shall be
produced.
Pressure sensor Measure the voltage
at pin No.1
(wire: yellow) DC12V
±
10%
Measure the voltage
at pin No.3 (wire:
blue) when the ink is
jetting. Pressure
[MPa] Output
voltage [V]
0.1 1.5 to 1.6
0.2 2.1 to 2.2
0.3 2.7 to 2.8