JLG 3969electric ANSI Service Manual - Manual (Page 17)

SECTION 2 - PROCEDURES
3120768 – JLG Sizzor –
2-5
General Features
Diagnostics
To obtain flash code, depress enable switch and repeat
operation which caused fault. After fault occurs, maintain
function position and read flash code.
NOTE: Flash code repeats after pause.
Flash code readings must be taken from platform
control box with unit switched to platform
NOTE: Refer to Troubleshooting Section 3 for specific flash
code troubleshooting information.
2.10 CYLINDER CHECKING PROCEDURES
NOTE: Cylinder checks must be performed any time a cylin-
der component is replaced or when improper system
operation is suspected.
Cylinder Without Counterbalance Valves
(Steer)
1. Using all applicable safety precautions, activate
hydraulic system and fully extend cylinder to be
checked. Shut down hydraulic system.
2. Carefully disconnect hydraulic hose from retract port
of cylinder. There will be initial weeping of hydraulic
fluid which can be caught in a suitable container.
After initial discharge, there should be no further
leakage from the retract port.
3. Activate hydraulic system, and activate cylinder
extend function.
4. If cylinder retract port leakage is less than 6-8 drops
per minute, carefully reconnect hose to retract port
and retract cylinder. If leakage continues at a rate of
6-8 drops per minute or more, cylinder repairs must
be made.
5. With cylinder fully retracted, shut down motor and
carefully disconnect hydraulic hose from cylinder
extend port.
6. Activate hydraulic system and activate cylinder
retract function. Check extend port for leakage.
7. If extend port leakage is less than 6-8 drops per
minute, carefully reconnect hose to extend port,
then activate cylinder through one complete cycle
and check for leaks. If leakage continues at a rate of
6-8 drops per minute or more, cylinder repairs must
be made.
Cylinders With Single Counterbalance Valve
(Lift Cylinder)
OPERATE ALL FUNCTIONS FROM GROUND CONTROL STATION
ONLY.
1. Using all applicable safety precautions, activate
hydraulic system.
2. Raise platform completely and place a suitable over-
head lifting device approximately 1 in (2.5 cm) below
the platform.
3. After completing the above, shut down hydraulic
system and allow machine to sit for 10-15 minutes.
This is done to relieve pressure in the hydraulic
lines. Carefully remove hydraulic hoses from appro-
priate cylinder port block.
4. There will be initial weeping of hydraulic fluid, which
can be caught in a suitable container. After the initial
discharge, there should not be any further leakage
from the ports. If leakage continues at a rate of 6-8
drops per minute or more, the following cylinder
repairs must be made. If the retract port is leaking,
the piston is leaking, the piston seals are defective
and must be replaced. If the extend port is leaking,
the counterbalance is defective and must be
replaced.
5. If no repairs are necessary or when repairs have
been made, carefully reconnect hydraulic hoses to
the appropriate ports.
6. Remove lifting device from platform, activate hydrau-
lic system and run cylinder through complete cycle
to check for leaks and operation.
Table 2-1. Flash Codes
Code Description
LED On Controller Operational
LED Off Internal fault or power not turned on
1 Flash Internal fault
2 Flashes Procedure fault
3 Flashes Motor permanently low
4 Flashes Motor permanently high
5 Flashes Motor neither low nor high (Open circuit)
6 Flashes Faulty drive hand controller
7 Flashes Low battery voltage
8 Flashes Thermal cutback, controller
10 Flashes Tachometer fault
11 Flashes Tachometer out of calibration