Hitachi UX Twin Nozzle, Service Manual

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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