Service manual

Electrical Service Manual V4.0
2
2-4
CURTIS 1203A CONTROLLER
Machine will not move.
Suspected bad t
hrottle system
Raise machine
drive wheels and
support with
suita
ble stands.
Attach the (-) lead of a DC
voltmeter to the B(-) terminal.
With the (+) lead measu
re the
voltage at the G
REEN wire on
the 6 pin connector on the
Curtis con
trol. Rotate the speed
know slowly back and forth
Turn the machine
power on and
THEN tap
e down
handle bar
button(s).
Did the meter
display a sweeping
voltage fro
m about 0
volts to 5 volts?
Remove the tape
from the handle
bar buttons and re-
mea
sure for
vo
ltage
Did the meter
stay at zero?
The potentiometer
system is working
properly
Disconnect the
rev
erse switch and
retest for voltage at
the g
reen wire
Did the meter
stay at zero?
The reverse switch is
bad. Replace the switch
A handle bar button is bad.
Check each one for continu
ity
and replace the one w
ith
constant continuity
YES
NO
YES
NO
YES
Attach the (-) lead of a DC
voltmeter to the B(-) termina
l.
With the (+) lead measure the
voltage a
t the center terminal of
the speed potentiometer.
Rotate the spee
d know slowly
back and forth
Did the meter
display a sweeping
voltage fro
m about 0
volts to 5 volts?
Check the wiring to and from
the handle bar button a
nd the
buttons themsel
ves.
YES
NO
With a DC voltmeter measure
fro
m the the right outside
terminal to the left outsid
e
ter
minal on the potentiometer
Did the meter
display between 5.0
and 4.5 vol
ts?
The potentiometer
is b
ad
YES
NO
With a DC voltmeter measure from
Pin #5 t
o Pin #7 on the 16 pin Molex
connector on the Curtis control.
NO
Did the meter
display between 5.0
and 4.5 vol
ts?
The Curtis control has
failed
. Replace control.
NO
Repair the wiring between
the Curtis control and the
po
tentiometer.
YES