March 2008 "3072RT / 3772RT / 3772RT HD" Service & Parts Manual - ANSI Specifications
Page 4-6
PROBLEM PROBABLE CAUSE REMEDY/SOLUTION
Multi-Function
No drive or Lift function from
Upper Controls with steer
operational
PWM circuit board in Platform Controls box not
functioning correctly
Proportional valve malfunction
EC1 pressure compensation valve not
functioning
SV2 not functioning
Faulty lift/drive selector switch
Faulty steer switch
Steering Cylinder/s internal leakage
RV1 steer relief valve not functioning
Check battery + and - terminals at board.
Check PWM output at A terminal.
Check connections between A terminal and Proportional valve.
Check, for 1 AMP at valve during full Joystick stroke. Replace
Proportional valve SP-1
Check, replace valve EC1
Check voltage and ground to valve
Check for faulty SV2 valve
Check power on wire #25A on switch
Check switch in Joystick handle
Check for internal leakage - repair
Check adjustment or replace
No steering With Drive
operational
continued…
Drive
No Mid Speed SV3 or SV4 powered and/or shifted
Speed/Torque selector switch malfunction
Speed/Torque selector switch inoperative
Faulty diode block DB1
Valve SV4 not functioning
EP2 poppet valve not functioning
No High Speed
These valves should not have 12 volts, in mid-speed, check
valve function
Should not have power at terminals 1 & 3 of Speed/Torque
switch in Platform Controls box with drive enabled
Check for 12 volts on all terminals of Speed/Torque switch in
Platform Controls box with drive enabled
Test DB-1 in Platform Controls box.
Check voltage and ground to valve
check for faulty valve spool
Check or replace valve
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