User Manual

16
TROUBLESHOOTING GUIDE — TM, TMS
Before performing any task, always lower the carriage fully to the floor and disconnect the power supply.
Consult the manufacturer for problems not addressed below.
* Check the DC notes page for troubleshooting other problems specific to battery-powered units.
Problem:
Power unit doesn’t run when “UP”
button is pressed.
Motor runs properly, carriage doesn’t
raise. Motor and pump not noisy.
Motor or control enclosure hums,
chatters, or buzzes, or some type of
squeal can be heard; the carriage
does not move, or the carriage
moves only slowly.
Carriage raises, then drifts down.
Carriage lowers too quickly.
Carriage lowers too slowly.
Carriage won’t lower.
Spongy or jerky carriage motion.
Possible cause(s):
No supply voltage (AC).
Upper-travel limit switch is engaged or
bad.
Bad connection in control circuit.
No control voltage (AC).
Bad motor relay coil.
Battery voltage low (DC).
Motor rotation is wrong (AC).
Pump has failed.
Fluid level is low.
See second item above, for when
carriage doesn’t raise.
Excess voltage drop to motor, due to
power wire size too small, wire run
too long, or incoming voltage too
low (AC).
Motor is “single-phasing” (AC).
Contamination holding open the
lowering valve or the check valve.
See last paragraph, above.
See above.
Flow control spool is stuck.
Flow control spool is stuck.
Pinched hose.
Velocity fuse locking (carriage only
slowly creeps down.)
Velocity fuse locking.
Control transformer (AC).
No supply voltage (AC).
Valve solenoid is bad.
Bad connection in control circuit.
Physical blockage of the structure.
Solenoid valve or suction hose screen
plugged.
Excessive air in the hydraulic
cylinders.
Action:
Test with meter. Check fuses,
breakers, and overloads to
determine the cause.
Inspect and test switch. Replace if
bad.
Test all circuits with meter.
Check for 24 VAC at control
transformer’s secondary; replace
fuse if blown.
Test with meter; replace if bad.
Test with meter. Charge battery if low
(is motor relay LED on?).
Verify motor shaft rotates CCW.
Consult factory for replacement.
Ensure reservoir is filled.
Same as above.
Check power installation for adequacy.
Check incoming voltage while motor
is running . Correct problem found.
Determine cause of loss of voltage on
one phase; correct.
Remove and inspect. Clean per
instructions in this manual.
Same as above.
Same as above.
See below.
Remove plug from FC port; push on
flow spool to ensure it is fully
pressed into the cavity.
Check pressure, supply, and return
hoses for kinks.
Same as for jerky carriage motion.
Same as for jerky carriage motion.
Test with meter; replace if bad.
Check for 24 VAC at secondary;
replace fuse if blown.
Check with multimeter on diodecheck
function. (Reading for ohms will not
provide an accurate test of the coil.)
Test all of circuit with meter.
Inspect for foreign material or objects
blocking the carriage.
Remove and inspect. Clean per
instructions in this manual.
Bleed air per procedure described in
this manual.