Pedals; Speed Potentiometer - Husqvarna 967187001 Workshop Manual

Manual CST tests

13.5 Pedals

This box shows the signal from the speed
potentiometer, the signal from the Forward pedal
and the Reverse pedal plus the signal from the
P-brake pedal. When moving forward with the
machine, it should say Forward pedal Active and
P-Brake signal not engaged, then a rising signal is
obtained on the graph for the speed potentiometer
depending on how far the pedal is pressed. If the
machine is driven but it is perceived as going too
slow, but it does move forward, first check that the
signal on the graph for the speed potentiometer
rises to at least 70 % of the scale. You can then
look at the "Miscellaneous" box and then the Motor
Speed Feedback graph. This graph shows the
speed of the drive motor on its output shaft, the
signal should reach up to 1.7 V at full speed on
level ground. If the machine does not come up
to speed, it may be due to the pedals not being
calibrated.

13.6 Speed Potentiometer

This graph is used to see when it is possible
to activate the potentiometer for forward and
reverse. Activation is done by pressing one of the
pedals, the pedal for forward activates (turns) the
potentiometer more than the reverse pedal.
The test reads off what CCU is indicating on the
input and displays it on the graph.
The potentiometer is turned by a mechanical
coupling between the pedals and the
potentiometer. On the potentiometer is a plastic
drive disc that converts pedal movement to a
rotating movement. In case of a fault indication,
this drive disc must be checked to see if it is
damaged.
128
English –
In this connector there are three leads, one
orange, one gray and one blue. If the connector is
unplugged from the potentiometer and the orange
cable coupled with the gray cable, "max" should be
displayed in CST. +5 V is then coupled directly to
the gray cable running straight into CCU via Cable
1 and it connects to CCU via connector D:7.
Jumpered for
max speed signal.
If the lead is coupled between the blue and the
gray lead in the connector instead, the graph
should display the "min" value.
If the tests show the result is OK, there is
something wrong with the potentiometer or the
connector transition to the potentiometer. There
is also a possible fault if the receptacles, in the
connector to the potentiometer, do not make
contact with the pin inside the potentiometer due
to oxidation or the receptacle being too worn.
The potentiometer can be read with a multimeter
set to measure ohms. The result should be
about 5000 ohms between the outer pins of the
potentiometer and measuring between the middle
pin and one of the outer pins, the resistance
should vary between zero and close to 5000 ohms
by turning the driver disc.
If the readings are OK and there is still no
indication in the resistance measurement with the
potentiometer connected, but there is an indication
in CST when a wire is connected to the connector,
then there is poor contact between the receptacles
in the connector to the potentiometer and the pin
inside the potentiometer.
If a max deflection on the graph is not obtained
GND
when a lead is connected between the orange
Signal
and the gray leads, there is probably a break in
the gray lead provided there is +5 V on the orange
+5V
lead receptacle. Measure the orange lead to
GND with a multimeter set to measure volts and it
should read about +5 V. If +5 V is OK, check that
the gray lead running from the potentiometer to
CCU, this is found only in Cable 1.
Jumpered for
min speed signal.
GND
SIGNAL
+5V
GND
SIGNAL
+5V