Platform Will Not Lift Up Using Platform Control; Mast Troubleshooting - JLG 10VP Service And Maintenance Manual

SECTION 3 - TROUBLESHOOTING

3.9 MAST TROUBLESHOOTING

Platform Will Not Lift Up Using Platform Control

Overview Of Procedure
This procedure examines the complete pump motor, ground control and pump valves electrical circuits.
Check For These Obvious Conditions First:
• Battery voltage 24 volts. (Fully charge batteries)
• Platform loaded within maximum allowable capacity.
• Hydraulic oil is within it's specified operating temperature range.
STEP
1. Will platform lift from ground control switch?
Note: Key switch must be set to GRND to test this.
Does pump motor run?
2.
3. Are the down and dump valves opening/closing properly?
Note: If machine will not lift and hydraulic oil is visible flowing in the
hydraulic tank, the dump valve is stuck in the open position.
4. Is the pressure set properly on the pump?
Is the lift cylinder OK?
5.
6. Are the mast sections operating freely?
3-30
Table 3-20. Platform Will Not Lift Up Using Platform Control.
ACTION SPEC
—
—
—
—
—
—
– JLG Lift –
YES NO
Go to Step 2 See (Figure 3-24)
See Pump Circuit
Go to Step 3 Check
(Table 3-21 )
See Pump Valves
Go to Step 4 Circuit Check
(Table 3-22 )
Set to correct
pressure specifi-
Go to Step 5
cation per this
Service Manual
Rebuild or
Go to Step 6
Replace Lift Cyl.
Check Mast,
Consult
Rebuild
Factory
if Necessary
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