50
- FORM NO. 56043071 CMAX
™
28/34ST / I-MAX
™
28/32C, BA 750/850ST, BA 750C
WHEEL DRIVE SYSTEM
FRONT
N
P
M
O
Q
R
Paddle forward
stop screw
Centering springs
(return to neutral)
5K POTENTIOMETER TESTING AND REMOVAL
WARNING!
Disconnect batteries at the battery pack disconnect before servicing.
Testing the 5K Potentiometer
Note: The potentiometer (pot) doesn’t have to be removed from its housing mount to test.
1
See Figure 8. Remove the front drive paddle Cover
(M)
from the rear housing
(N)
held together with (4) item
(O)
Screws.
2
See Figure 9. Observe the 3 wires connected to the pot and disconnect. Note the proper wire numbers and/or colors and their terminal
connections for re-assembly.
3
Test the Pot
(P)
using an ohmmeter, the potentiometer specification is 5K Ohms. Connect the meter leads to each of the outside connections
(3 high & 1 low, shown in Figure 9) on the pot, it should read approximately 5000 ohms (range 4500-5500 ohms).
4
Next, take the 3 high pot connection test lead and connect to the middle connection (2 wiper), then push and pull the rear cover to turn the
shaft in both directions. The readings should be approximately half the total resistance (2500 ohms) towards 5000 ohms and 2500 ohms
towards 0 ohms. Example “A” total resistance of pot 4840 ohms (3 high/1 low) test connections. Example “B” test middle connection (2
wiper) and outside rear (1 low) Fwd reading 2420 ohms to 4700 ohms, Rev 2420 ohms to 230 ohms.
5
Testing Summary: The above tests are to show the increase and decrease of the pot through its working range. If you do not get similar
readings replace the Potentiometer
(P)
.
Potentiometer Removal
6
See Figure 10. Loosen the pot shaft anchor nut and unthread it to the end of the shaft.
7
Back out the Screw
(Q)
from the pot Fork
(R)
.
8
Maneuver the pot out from its mounting bracket hole and separate the Fork
(R)
from the shaft end.
9
Finish unthreading the anchor nut from the end of the pot and then remove the pot completely from the handle mount.
10
To reinstall a potentiometer see the adjustment section below in this manual section.
POTENTIOMETER INSTALLATION AND ADJUSTMENT
WARNING!
The adjustment of the potentiometer is to set the drive paddle for a neutral drive motor operation. If the potentiometer is not adjusted
properly, the machine could move on its own, in either FWD or REV without any operator input.
1
See Figure 10. Install lock washer (on pot side), pot and anchor nut to the handle mount bracket as shown. NOTE: Do not completely tighten
the anchor nut at this time.
2
Using an ohmmeter connect leads to the middle terminal (2 wiper) and the (1 low pot) outside terminal. Then pre-set, turn the shaft to
approximately 2500 ohms.
3
Install the Fork
(R)
onto the pot shaft, then tighten the
(Q)
Screw.
4
Then without turning the pot shaft thread the anchor nut just enough to seat the pot to its mounting bracket.
FIGURE 8