Hitachi IJ PH Service Manual page 118

(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 electric parts (pump motor, solenoid valves, and pressure sensor) are not
operated in any case other than the above, make the following checks first.
When the criterion is satisfied, the power supply, EZJ93 board, wire, or connector
is abnormal.
Part
Pump motor
Solenoid valve
Pressure sensor
Check method
(1)Operate the pump
on the "Solenoid
Valve/Pump Test"
screen.
(2) Measure the
voltage at pin
No.5 (wire: red)
(1) Replace the
solenoid valve and
the connector with
another normal
solenoid valve and
connector.
(2) Make a check on
the "Solenoid
Valve/Pump Test"
screen. Release
the solenoid
valve.
Measure the voltage
at pin No.1
(wire: yellow)
Measure the voltage
at pin No.3 (wire:
blue) in the ink jet
status.
4-29
Criterion
20 V DC or more
An operation sound can be
confirmed.
DC12V±10%
Pressure Output
[MPa] voltage [V]
0.1 2.0 to 2.3
0.2 3.2 to 3.5
0.3 4.3 to 4.6