Mec Speed Level 2684 RT Service And Parts Manual page 172

LIFT/LOWER
Platform will not raise; Excessive weight on platform
electric motor
operating.
Lift Relief Valve RV-1 out of adjustment
Lift Valve SV-1 not energized
Lowering Valve SV-5 stuck open (located at
base of lift cylinder)
Main system pressure inadequate
Platform will not raise; Level sensor out of level (platform elevated
electric motor NOT above10')
operating.
Batteries discharged
System interlock
Platform raises Lift Valve SV-1 sticking
uncommanded when
operating other
functions
Shuttle Valve LS-2 damaged or
contaminated
Platform will not lower Maintenance lock in maintenance position Return maintenance lock to the stowed position
or lowers slowly
Lowering valve not energized
Lowering valve not shifting
Lowering orifice plugged
System interruption
Platform lowers Lowering Valve SV-5 sticking or
uncommanded (drift contaminated
down)
Cylinder internal seal failure
Emergency lowering not Lowering valve not shifting
working
Lowering Orifice ORF-3 plugged
Emergency Down battery discharged
Emergency Down supply fuse blown
Valve coil failed on cylinder
DRIVE:
No drive function Drive Valve not shifting
Lift/Drive select switch malfunction
Drive system interlock
Drive operates Drive Valve SVD-1 sticking or damaged
uncommanded when
operating other
functions
Shuttle Valve LS-3 damaged or
contaminated
November 2009
Page 4b-30
T - 3 0 8 4 E S
R O U B L E S H O O T I N G
"3084 Speed Level™ Sigma Lift" Service and Parts Manual
- - T
M O D E L R O U B L E S H O O T I N G
Reduce weight to rated platform capacity
Adjust relief valve to rated platform capacity
Check wiring to lift valve. Check for EZ-Cal message or flash
code
Check and remove contamination from valve
Check pump output pressure
Reposition machine to firm level surface. Check level sensor
function using EZ-Cal See Diagnostic chart 2e1
Will receive 4-4 or 7-7 flash on GP400. Clean, service and
charge batteries
Battery charger may not operate if battery voltage drops
below 20 volts
Check HELP messages using EZ-Cal
Clean or replace SV-1 valve
Clean or replace LS-2 valve. See hydraulic diagram for
location
Check wiring to lowering valve located on Lift Cylinder.
Check for EZ-Cal message or Flash code
Clean debris. Check for damage, replace
Clean orifice located inside hose fitting on lift cylinder
Check HELP messages using EZ-Cal
Deploy Maintenance Lock!
Remove and clean or replace lowering valve SV5
Check, repair seals
Clean debris, check for damage, replace
Clean orifice, located in Lift cylinder hose port.
Charge, check charge diode & connections
Replace fuse, check for shorts in wire and coil
Test, replace
Check electrical connections at drive valve, check drive valve
for contamination.
Check continuity through switch
Check HELP and MODE messages on EZ-Cal
Clean, replace SVD-1 valve. See hydraulic diagram.
Clean or replace LS-3 valve. See hydraulic diagram for
location
C
H A R T