Daewoo Solar 225LC-V Shop Manual page 247

To verify adequate available hydraulic flow, before any other tests are performed through the circuit:
Check engine operation -
• at 2,100 RPM with no load (Model Solar 225LC-V)
• at 2,150 rpm with no load (Models Solar 225NLC-V, 255LC-V)
• at 1,950 rpm with no load (Models Solar 300LC-V, 300LL)
• at 1,950 rpm stall load (Models Solar 225LC-V, 300LC-V, 300LL)
• at 2,000 rpm stall load (Model Solar 225NLC-V, 255LC-V)
If engine rpm drops excessively with a load or fails to surpass rated speed (1,900 rpm), performance
problems may be due to inadequate hydraulic flow caused by lagging rotational speed.
NOTE: Verify actual flow on the excavator against rated performance, with a flow meter.
If engine tests meet specifications and adequate torque and horsepower are available at the pump drive
flex coupling, pull out the electrical tray under the operator's seat to inspect the self-diagnostic display.
If the EPOS trouble code display is clear, check hydraulic functions in the following sequence:
• Pilot pressure
• Negacon, negative control pressure
• Main relief pressure (front and rear pump)
• Swing pressure
• Port relief pressure (individual control functions; boom, arm, bucket, swing, and travel)
• Power boost circuit
• Standard performance tests; cylinder speed, hydraulic motor (travel and swing) speed, cylinder
oil-tightness "permissible drift" test
NOTE: System specification performance tests of individual activator function are determined by
flow rate through the component or circuit, not the control pressure or system pressure
available to the actuator. Poor flow through the individual circuit may indicate that the
component is worn beyond tolerance limits, while all other hydraulic functions are
adequate.
It is suggested that the troubleshooter maintain the testing sequence of the preceding list.
Checks and adjustments nearer the middle or the end of the list may depend on adequate
functioning of systems tested nearer the top of the list.
Hydraulic System Troubleshooting, Testing and
Adjustment
IMPORTANT
S0702170K
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