Upright TM12 Service & Parts Manual page 64

Troubleshooting
Table 4-1: Cause and Remedy (Continued)
No drive reverse but
drives in forward. Lift
function operable.
No drive reverse but
drives in forward. No
Platform will not
elevate or elevates
Platform drifts down
after being elevated.
Platform will not
lower. Drive function
Motion Alarm does
Brake will not lock
Page 4-4
TROUBLE
1. Faulty Drive/Lift Selector Switch
3. Faulty Reverse Coil
4. Faulty Counterbalance Valves
1. Faulty Drive/Lift Selector Switch
2. Faulty Controller
lift functions.
3. Faulty Down/Reverse Relay
1. Emergency Down Valve open
2. Platform overloaded
slowly.
4. Faulty Lift Valve Coil
5. Faulty Drive/Lift Selector Switch
6. Lift Relief Valve out of adjustment or faulty
7. Drive/Lift Valve sticking
8. Faulty Up/Fwd Relay
9. Faulty Controller
10. Faulty Lift Flow Control
1. Emergency Lowering/Down Valve partly
1. Faulty Down Valve Coil
operable.
2. Faulty Drive/Lift Selector Switch
3. Down Valve stuck
4. Plugged Down Orifice
5. Velocity Fuse Valve sticking or frozen
1. Faulty Down Alarm
not sound.
Brake will not 1. Brake Orifice plugged
release.
2. Faulty Brake Cylinder
3. Brake out of adjustment
1. Brake Orifice plugged
wheel.
2. Faulty Brake Cylinder
3. Brake out of adjustment
PROBABLE CAUSE
2. Faulty Diode
Check pressure of Counterbalance Valves. Replace or reset valves
3. Faulty Diode
Ensure that the Emergency Lowering Valve is completely closed.
open or faulty
Test Down Valve Coil. If proper voltage is present and coil is not
With the Drive/Lift Switch in the LIFT position, check continuity.
Repeat lifting and lowering platform to warm oil, if possible move
machine out of cold environment, replace the Velocity Fuse Valve.
2. Faulty Relay
4.2 - Cause and Remedy
REMEDY
Test Drive/Lift Switch for continuity. Replace if faulty.
Test Diode. replace if faulty.
Test Reverse Coil, if proper voltage is present and coil is not
magnetized, replace.
as required.
Test Drive/Lift Switch for continuity. Replace if faulty.
Check operation of Controller Switch. Replace if required.
Test Relay, replace if faulty.
Close Emergency Down Valve.
Observe maximum load rating.
Test Diode, replace if faulty.
Test Lift Valve Coil. If proper voltage is present and coil is not
magnetized, replace.
Test Drive/Lift Switch for continuity. Replace if faulty.
Adjust the Lift Relief Valve. If not adjustable, replace.
Replace the Lift Valve.
Test Relay, replace if faulty.
Check operation of Controller. Replace if required.
Replace Flow Control.
Replace the valve.
magnetized, replace.
Replace if defective.
Replace the Down Valve.
Remove and clean orifice.
Check voltage to Down Alarm. If proper voltage is present,
replace the Alarm.
Test Relay. Replace if faulty.
Remove and clean Orifice.
Check and replace seals in Brake Cylinder.
Adjust nut to disengage brakes from tires when driving only.
Remove and clean Orifice.
Check and replace seals in Brake Cylinder.
Adjust nut so brakes fully engage tires when not driving.
TM12 Work Platform - European