FG00092
PARTS - SERVICE
8/17/99
GRAM
B470, B471, F138
TO: ALL HYSTER INDUSTRIAL TRUCK DEALER PRINCIPALS, SERVICE MANAGERS
AND PARTS MANAGERS
Subject: N-XMR2 Potentiometer Replacement and Setup Procedure
Description:
To enable your technicians to properly setup and calibrate the potentiometers in the Fast
Track control handle, the following procedures have been developed to assist you with
installation and setup.
Control Handle Potentiometer Removal:
1. Disconnect the battery.
2. Remove the top cover.
3. Grip the bottom edge of the control handle boot and roll it upward to access the dual axle
mechanism.
4. Disconnect the potentiometer plug connector from the main truck wire harness.
5. Loosen the set screw holding the shaft of the potentiometer in the pivot shaft.
6. Remove the screw holding the potentiometer bracket to the dual axle mechanism.
7. Remove the potentiometer assembly from the dual axle mechanism.
8. Remove the lock washer and lock nut on the collar of the potentiometer and remove the
potentiometer from the mounting bracket. Remove and save the nylon washer for use on
the replacement potentiometer.
Control Handle Potentiometer Replacement:
1. Before mounting replacement potentiometer into mechanism, verify the potentiometer
overall resistance with an ohm meter. Check the resistance between the black and brown
wires. The overall resistance should measure between 8K and 12K.
We reserve the right to make changes in design or add improvements without incurring the obligation to make such changes in equipment
previously manufactured.
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Page 2 of 3
Control Handle Potentiometer Replacement: (Continued)
2. To obtain potentiometer center position, turn the potentiometer shaft until the resistance
value equals ½ of the overall resistance measured. Check the resistance between the
potentiometer red and black wires then between the red and brown wires. Center the
potentiometer within 200 ohms or less. Check the potentiometer linearity with an
ohmmeter; make sure the potentiometer has a clean sweep in both directions observing
the range of deviation.
3. During potentiometer sweep, resistance should be linear and consistently increase or
decrease, depending on direction, i.e.: Moving the potentiometer in one direction
resistance should not reverse (example: 1K ohm, 1.5K ohm, 3K ohm). Replace
potentiometers with this problem. Minimal "flat spots" with little or no ohm change while
moving the potentiometer shaft is acceptable.
4. Place the nylon washer and then the mount bracket over the collar of the new
potentiometer and secure with the lock washer and nut. Be sure the cable is oriented to
the bend of the bracket. (Calibrate the potentiometer to the center position).
5. Slide the potentiometer shaft into the hole in the end of the axle shaft.
6. Screw the bracket onto the dual axle mechanism.( 1Hex head socket head cap screw, 1
flat washer)
7. Make sure the flat on the potentiometer shaft is facing the setscrew then tighten the
setscrew.
8. Verify the potentiometer center position is maintained again by checking the resistance
between the potentiometer red and black wires then between the red and brown wires.
Check that the potentiometer is centered within 400 ohms or less. If the potentiometer is
not centered, loosen the cap screw slightly to move the bracket and potentiometer
simultaneously to obtain center position.
9. Once center is obtained, tighten the cap screw then loosen the setscrew and retighten.
This will relieve any tension on the potentiometer shaft.
10. With an ohmmeter connected to the potentiometer, operate the control handle through the
full range of motion and using your finger, tap on the body of the potentiometer while
testing the sweep. During potentiometer sweep, resistance should be linear and
consistently increase or decrease, depending on direction, i.e.: Moving the potentiometer
in one direction resistance should not reverse (example: 1K ohm, 1.5K ohm, 3K ohm).
Replace potentiometers with this problem. Minimal "flat spots" with little or no ohm change
while moving the potentiometer shaft is acceptable.
We reserve the right to change the design of our products without incurring an obligation to modify previously manufactured. product
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Page 3 of 3
Control Handle Potentiometer Replacement (Continued):
11. Wire-tie the potentiometer wire to the mounting bracket and route the wire through the
loom clip. Plug the connector into the main truck wire harness. Operate control handle
through full range of motion to verify that the wires do not rub or chafe on any edges. Add
additional wire ties as necessary.
. CAUTION!
12. Calibrate potentiometer to MIB Make sure you remove your hand from the
control handle before performing this procedure. Calibrate the potentiometer to the MIB.
(Refer to MIB set up and calibration in SRM 719 starting on page 20). At step 5, page 22,
while performing item 4 of step 5, make sure the handle is exactly in the neutral position.
The MIB  learns the neutral position during this function.
13. Return the control handle boot to the normal operating position.
14. Install the top cover.
15. Connect the battery.
Warranty Reimbursement:
The information contained herein is for informational purposes only and will not be considered
for warranty reimbursement unless a failure occurs within the standard warranty period.
We reserve the right to change the design of our products without incurring an obligation to modify previously manufactured. product