Komatsu Galeo PC138US-8, Shop Manual

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SEN02465-01 40 Troubleshooting
6
PC138US, USLC-8
Failure code [DAF8KB] Short circuit in camera power supply 1
User code Failure code
Trouble
Short circuit in camera power supply
(Machine monitor system)
— DAF8KB
Contents of
trouble
• Output power supply voltage (Rating: 8 V) from machine monitor to camera is below 6.0 V or above
10 V.
Action of
machine monitor
• Turns output power supply voltage (Rating: 8 V) to camera OFF.
• Even if cause of failure disappears, system does not reset itself until starting switch is turned OFF.
Problem that
appears on
machine
• Camera image is not displayed on monitor screen.
Related
information
• Method of reproducing failure code: Turn starting switch ON.
Possible causes
and standard
value in normal
state
Cause Standard value in normal state/Remarks on troubleshooting
1
Defective camera (Internal
short circuit)
a
Disconnect camera with starting switch OFF, then turn starting
switch ON and carry out troubleshooting.
Disconnect camera and perform failure reproduction operation. If
failure code disappears at this time, camera is defective.
2
Ground fault in wiring har-
ness (Contact with GND cir-
cuit)
a
Disconnect camera with starting switch OFF, then turn starting
switch ON and carry out troubleshooting.
(Disconnect camera and check that it is not defective in
advance.)
Between CM05 (female) (1) – CAMERA
(female) (F) wiring harness and ground
Voltage Min. 6 V
3
Hot short (Contact with 24V
circuit) in wiring harness
a
Disconnect camera with starting switch OFF, then turn starting
switch ON and carry out troubleshooting.
(Disconnect camera and check that it is not defective in
advance.)
Between CM05 (female) (1) – CAMERA
(female) (F) wiring harness and ground
Voltage Max. 10 V
4 Defective machine monitor
If causes 1 – 3 are not detected, machine monitor may be defec-
tive. (Since trouble is in system, troubleshooting cannot be carried
out.)