Curtis Speed Controller - Clarke CA90 32T Service Manual

Service Manual – CA90 32T

Curtis Speed Controller

NOTE: Replacing the Curtis Speed Controller is quite difficult. This unit has proven VERY reliable, and
99% of the time there are drive issues, the problem is something OTHER than the speed controller.
Before you change the Curtis Speed controller:
• Turn the keyswitch ON, and rotate the speed pot. to the lowest setting.
• Place your ear as close as you can to the top of the control housing.
• Pull the safety trigger(s) to engage the trigger switch.
• Slowly rotate the speed pot. clockwise, and listen.
• If you hear (1) click, the Curtis controller is fine, and the problem is "downstream". So it's either the
wiring, or the transaxle motor.
• If you hear (2) clicks, the Curtis controller is fine, and the problem is "upstream. So one if the inputs is
not correct. Trigger switch, Speed Pot., Direction switch, or wiring.
• If you hear no clicks at all, proceed with changing the Curtis controller.
1. Dis-connect the batteries.
2. Remove the (4) screws that attach the lower control housing panel.
3. GENTLY let it hang out of the way.
4. Use a "stubby" #2 phillips screwdriver to loosen the (4) screws that attach the speed control plate to the
rear of the control housing.
5. Disconnect the 18-pin white connector from the Speed controller.
6. Disconnect the (4) individual wires (B+, B -, M1, M2).
7. Carefully slide the Speed controller and plate out of the housing.
8. Remove the (2) phillips screws that hold the controller to the plate.
9. Reinstall the new Speed controller in the reverse order of the steps above.
Wheel System, Traction
(4) phillips screws
61