TM 5-3805-280-24-1
Diagnostic Information
Speed Sensing Solenoid Valve
Arm Regenerative Solenoid
Power Boost Solenoid Valve (SG)
(SD)
Valve (SC)
Operational Function
Sends a pilot pressure signal to
Sends a pilot pressure signal to load
Sends a pilot pressure signal to
temporary increase system relief
piston in pump regulators to reduce
shift the arm regenerative valve.
valve pressure setting.
pump flow.
Control Problems
No pressure signal sent to system
No pressure signal sent to load
No pressure signal sent to shift
relief valve. System relief valve
piston in pump regulators.
arm regenerative valve.
pressure setting does not increase.
Machine Symptoms
Digging or lifting force does not
Torque required to drive pumps
During arm in operation, there is
increase.
exceed engine output power. Engine
arm cylinder cavitation and
speed can decrease below rated
controllability becomes less.
speed.
Laptop Computer with
--
--
--
Excavator Diagnostic
Software Self-Diagnostic
Functions
Laptop Computer with
Monitor No. 12, Power boost control
Monitor No. 11, Speed sense control
Monitor No. 9, Arm regenerative
Excavator Diagnostic
pressure.
pressure.
control pressure.
Software Monitoring
Function
Harness Check
Install JT07062 Test Harness. Check
Install JT07062 Test Harness.
Install JT07062 Test Harness.
that indicator light is on.
Check that indicator light is on.
Check that indicator light is on.
Notes
If indicator light is off, check wiring
If indicator light is off, check wiring
If indicator light is off, check
harness.
harness.
wiring harness.
Description of Operation
See Power Boost Control Circuit
See Engine Speed Sensing Control
See Arm Regenerative Valve
Operation in Group 9025-25.
Circuit Operation in Group 9025-25.
Operation in Group 9025-05.
9025
15
4
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TX,15,GG2238
1913AUG983/10
6-93