Lifting Arms 397
Case of a HELPING-HAND™ arm moving very slowly or not moving
at all in one direction
If the HELPING-HAND™ arm of your EXPERT™ unit is moving up/down or in/out very slowly or not
moving at all in one direction or the other, chances are it may be due to low voltage proportional
signals.
NOTE: The following procedure may also be used to correct other problems with the lift arm such as
the arm moving by itself.
To resolve this problem proceed this way:
1. Identify the wires connected to the coil on the proportional valve via the connector (see Figure
10-24).
2. Secure the arm working area using barrier tape or barricades.
3. Remove the connector from the coil.
4. Start the engine.
5. Engage the hydraulic pump.
6. Using a voltmeter or multimeter, check the voltage status of the 12V wire (806A or 806B) with
the ground wire (105B) to make sure it is at the correct voltage.
This is the first test (see Figure 10-23).
NOTE: The input voltage should be at 12V for the arm to work properly.
7. Check the mid-range signal by depressing the deadman switch on the arm joystick.
Do not move the joystick.
The mid-range signal voltage should be around 6V and the lift arm should not move.
8. Using a voltmeter or multimeter, check the voltage status of the signal wire (811B or 807B) with
the ground wire (105B) to make sure it is at the correct voltage.
This is the second test (see Figure 10-23).
The correct signal voltage should be between 3V and 9V, with the mid-range signal voltage at 6V.
NOTE: The voltage values of 3V and 9V are theoretical values and may slightly differ from the actual
values.
For this test, you need to move the joystick with the deadman switch depressed:
8 a. Activate the up/down function by moving the joystick in one direction, then the other.
The further away the joystick is from its neutral position, the faster the arm moves.
When you move the joystick to the maximum in one direction, the signal voltage should be
either 3V or 9V. If it is 3V in one direction, it would be 9V in the other. The speed by which
the arm moves when the joystick is pushed to the fullest is the same, no matter which
direction the arm travels.
When the joystick gets closer to its neutral position, the arm slows down and when it
returns to its neutral position, the arm stops completely (see Figure 10-22).
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