Mec 3072RT - Page 75

"3072RT / 3772RT / 3772RT HD" Service & Parts Manual - ANSI Specifications March 2008
Page 4-5
PROBLEM PROBABLE CAUSE REMEDY/SOLUTION
Drive
No drive function Valve SVD1 not energizing
brakes not releasing
Proportional Control out of adjustment
(High Speed adjustment)
Outriggers lowered
Outrigger Retracted switch/s inoperative
Proportional Control out of adjustment
(Low Range adjustment)
Jumper - axle float bypass missing from circuit
board, Lower Controls box
Outriggers lowered
Unit out of level
High torque enabled
Limit switch not functioning
Upper Controls circuit board running in slow
speed mode
Proportional Control out of adjustment
(Low Range adjustment)
Engine not running to full potential
Wheel motor/s not functioning correctly
RV3 or RV4 not adjusted correctly
Rev-Up or FWD-Down micro-switch failure
Drive valve SVD1 not energizing in one direction
Counterbalance valve CBV1 or CBV2 not
functioning correctly
Speed/Torque selector switch inoperative
Valve SV3 not functioning
EP1 poppet valve not functioning
Check forward/reverse LEDs lighting up at circuit board inside
Lower Controls box
Check connections at valve
Check voltage at valve
Check ground to valve
Check valve for proper functioning
Check OD1 brake orifice for contamination
See Proportional Controller Adjustment in this section
Check Drive Enable light - raise outriggers
Check enable light on Platform Controls box
Check outrigger switches located on top of each outrigger jack
for continuity
See Proportional Controller Adjustment in this section
Forward Reverse LEDs not lighting up at Lower Controls circuit
board? Install jumper wire.
Check Drive Enable light - raise outriggers
Lower and reposition the machine.
Check Level Sensor malfunction
Check Speed/Torque switch in Platform Controls Box
Limit switch at left-rear of base
Check continuity between wire 2 TAN/ORG and wire 20 RED/
WHT. Continuity = platform stowed.
12 volts to “R” terminal on circuit board in Platform Controls
box = High Range
See Proportional Controller Adjustment in this section
Check engine operation as per engine manufacturer guidelines
Inspect wheel motors for excessive bypass
Check and adjust relief valves
Check micro-switches on Joystick controller for function or
adjustment
Check 12 volts to appropriate coil, check coil, check valve
function
Swap Counterbalance valves to see if functioning direction
changes.
Check for 12 volts on terminals 2 & 3 of Speed/Torque switch
in Platform Controls box with drive enabled
Check for 12 volts and ground to valve
Check for faulty valve spool
Check or replace valve
No drive elevated
(with outriggers option)
continued…
Slow drive with Platform
stowed
(with outriggers option)
No low speed (high torque
mode)
Drive in one direction only