Mec 2633ES - Lift Function Issues (Continued); Platform Will Not Lower

"2033ES / 2633ES" Service & Parts Manual - ANSI Specifications October 2008
Page 4-7
PROBLEM REMEDY/SOLUTION
No lift from
either control
station - Pump
motor runs
Lift Valve SV2 not energized
Troubleshooting (continued)
POSSIBLE CAUSE
Check lift circuit on wire # 4 from control box to lift
valve SV2
LIFT (CONTINUED)
Main system pressure
inadequate
Check main relief RV2 adjustment, Check pump
output pressure using a flow meter
LOWER
Platform will
not lower
Micro-switch S7 inoperative
Check operation of micro-switch located in upper
control box on joystick
Maintenance lock in
maintenance position
Elevate platform slightly and return maintenance
lock to the stowed position
No lift from
either control
station - Pump
motor
NOT
operating while
attempting lift
Mode Selector Switch S6 faulty Check power through S6 on wire 10
Damaged wiring or poor plug
connection
Check wire 10 through plug connections from upper
control box to Diode Board
Failed diode in diode board Test diodes on diode board, replace diode board
Lowering valve/s not energized
SV9 (SV8)
Check lowering circuit wire # 5 from control box to
lowering valve, located on lift cylinder
On earlier units, check valve SV8 also
Lowering valve/s not shifting Clean debris, replace
Lowering orifice ORF3 plugged Clean orifice - located under fitting at lift cylinder
Emergency
lowering not
working
E-down cable frayed (later
models only)
Replace e-down cable
Lowering valve not shifting Clean debris, replace