JLG LSS Scissors - Manual (Page 43)

SECTION 5 - SERVICE - (LE, MRT, RTS, ES, RT)
3124288 – JLG Lift – 5-7
4. Damage to the platform or arm structure has occurred or one of the components is
out-of-tolerance.Twists in the platform, for instance, will cause huge off-axis forces to
be applied to the Shear Pin Load Cells, disturbing their primary measurement axis
readings. If Lift Up / Down is noisy or not smooth, examine this issue thoroughly.
Resolution is to replace the damaged or faulty component. Watch for Shear Pin Load
Cell damage (yield) as a result of this difficulty.
5. One of the Shear Pin Load Cells is contaminated by debris or moisture. Examine
each sensor’s reading using the JLG Analyzer. Proceed to the DIAGNOSTICS, CELL
1-4, LOAD displays and determine if the readings are reasonable and stable (not
changing by more than +2lbs (±1kg) (without the influence of vibration or wind).
Lack of measurement stability is a key indication of contamination. Unplug the
appropriate connector (J5 is CELL 1, J6 is CELL 2, J7 is CELL 3, and J8 is CELL 4)
and inspect for dirt or moisture. Look carefully into the female connector on the sen-
sor’s cordset for evidence of contamination. Debris should be brushed away with a
soft bristle brush (do not introduce any cleaners as they will leave conductive resi-
due). Moisture should be allowed to evaporate or accelerated with a heat-gun (use
low heat and be carefully to not melt connector materials). Moisture intrusion into the
molded portion of the connector (capillary action into the wire bundle) or the Shear
Pin Load Cell itself will require replacement of the sensor.
6. One of the Shear Pin Load Cells has been mechanically damaged (yielded). Any
Shear Pin Load Cell that is physically deformed or has damage to one of the stain-
less steel covers should be replaced immediately. It is also possible to have invisible
mechanical damage resulting from an extreme overload (>4200lbs [>1900kg] for
1.25 in diam.; >5700 lbs or 2600 KG for 2 inch diam.). This can be detected by sup-
porting the platform with an overhead crane and by removing the suspect sensor (no
weight resting on the Shear Pin Load Cell). Examine the sensor’s reading using the
JLG Analyzer. Proceed to the DIAGNOSTICS, CELL 1-4, LOAD displays and observe
whether the unloaded sensors read with +15lbs (±7kg) of zero (individually).
Replace sensors that read excessive force when physically unloaded.
7. The LSS Module is suspect. Interchange the Shear Pin Load Cell connections (J5-
J8) and observe the results via the JLG Analyzer. Proceed to the DIAGNOSTICS,
CELL 1-4, LOAD displays and observe the readings. If the problem seems to remain
with a particular sensor, carefully re-examine the issues above. If the problems
seems to remain with a particular LSS Module channel, substitute another module.
Table 5-3. LSS Troubleshooting Chart - Measurement Performance
Difficulty Possible Resolution