JLG 3969electric ANSI Service Manual - Manual (Page 32)

SECTION 3 - TROUBLESHOOTING
3-2
– JLG Sizzor – 3120768
Table 3-1. Platform Assembly Troubleshooting
TROUBLE PROBABLE CAUSE REMEDY
PLATFORM ELEVATION SYSTEM
No response to control switch Enable switch not activated Activate enable switch
Function not activated within 3 seconds after
enable switch was depressed Reactivate enable switch
Enable switch not functioning properly Replace enable switch circuit card
Lift control switch inoperative Replace control switch
Hydraulic oil system low Replenish oil system necessary
Restricted or broken supply line on valve or pump Clean, repair or replace as necessary
Control valve not functioning properly Repair or replace valve
Lift cylinder not functioning properly Repair or replace lift cylinder
Hydraulic pump not functioning properly Check Sevcon control contactors for proper func-
tioning
Low battery voltage Check voltage and charge batteries or replace
batteries as necessary
Platform will not raise Enable switch not activated Activate enable switch
Function not activated within 3 seconds after
enable switch was depressed Reactivate enable switch
Enable switch not functioning properly Replace enable switch circuit card
Load capacity exceeded. (Personnel and/or
equipment on platform) Reduce load to recommended capacity
Hydraulic oil system low Replenish oil as necessary
Restricted or broken oil line or fitting Clean, repair or replace as necessary
Control valve not functioning properly Repair or replace valve
Lift cylinder not functioning properly Repair or replace lift cylinder
Motor/Pump does not respond when lift control
switch is moved to the up position Refer to the electrical schematic and/or electrical
system troubleshooting chart
No electrical signal being sent to lift up control
valve cartridge Refer to the electrical schematic and/or electrical
system troubleshooting chart
Pressure set to low on pump Check pressure and reset as necessary
Platform will not lower No electrical signal being sent to lift down control
valve cartridge Refer to the electrical schematic and/or electrical
system troubleshooting chart
Lift down control cartridge not functioning prop-
erly Repair or replace lift down control cartridge
Lift cylinder not functioning properly Repair or replace lift cylinder