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Curtis PMC 1204X/1205X/1209/1221 Manual
While you have the potbox wires off the controller, use an ohmmeter to
3-C
check for shorts between these wires and the vehicle frame. You should see
a resistance of at least 1 megohm. If it is lower than that, inspect the wiring
for damaged insulation or contact with acid. If necessary, replace the potbox.
Push the wires back on the controller terminals. It doesn't matter which wire
3-D
goes on which terminal.
Inspect the terminal area of the controller closely. Occasionally a buildup of
3-E
dirt or acid residue of a conductive nature causes electrical leakage between
the throttle input terminals and the B- or M- terminals, leading to faulty
controller operation. To check for this problem, measure the voltage at the
appropriate throttle input terminal (the upper terminal for 0–5kΩ pots, the
lower terminal for 5kΩ–0 pots), by connecting the voltmeter (-) lead to the
controller's B- terminal. The keyswitch must be on and a direction selected
for this test.
Pedal up:
Pedal down:
Compare your readings with these; if they are different by more than a few
tenths of a volt, contamination is probably the cause.
Carefully clean off the terminal area of the controller with a cotton swab or
3-F
clean rag moistened with water, and dry thoroughly.
C A U T I O N
Now test the controller to see if proper operation is restored. If so, take steps
to prevent this from happening again: dirt and water must be kept from
reaching the terminal area of the controller. If the voltages are still out of
range, the controller is at fault and should be replaced.
TROUBLESHOOTING & BENCH TESTING
THROTTLE INPUT VOLTAGE
STANDARD
0–5kΩ
5kΩ–0
POT
UPPER TERMINAL
LOWER TERMINAL
2.7
7.0
Be sure to turn everything off
before cleaning.
(in volts)
POT
3.1
7.4
30
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