4qd 4QD-300-48 Manual de instruções - Página 16
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Imprimir página17 Fuse
A 'fuse' track is present on the controller: it is on the
base board. It is arrowed on the 'Features' diagram
(page 4). It is there to limit damage to the controller
in the event of an external wiring fault in the ignition
or parking brake wiring.
This fuse does not protect any of the controller's
electronics, nor can it be blown by any fault in the
controller. If it blows, the ignition will be off and the
controller will be dead.
Two empty fuse clips are provided on the board
where a standard 20mm fuse (1.0 amp) may be fitted
if the track blows. These are between the two boards
and the Features diagram has a section of the top
board 'cut away' to show their position.
The track to Pin F of the input connector also acts as
a fuse in the event of damaging earth fault currents
in the pot wiring.
If either track fuses find and repair the cause of the
fusing before proceeding.
Controllers returned for repair with only a fuse track
blown will be subject to a charge for handling, test
and carriage.
18 Fault finding
Most faults are caused by problems in the external
wiring.The controller has many safeguards to restrict
damage if there is a problem and an understanding of
the safeguards should assist in finding faults.
All voltage measurements should be made with meter
negative on the battery negative terminal.
The ignition switch applies battery voltage to pin C
of the 4 way connector. This enables the controller's
internal power supply. Until the internal supply is on
the controller is dead. The internal supply (+12v) can
be measured on pin B of the 6 way connector.
+12v is also applied (via pot fault detection circuitry)
to the top of the throttle pot, pin D, where you should
measure around 11.4 volts.
As the throttle pot is moved it applies a variable
voltage back to pin E of the 6 way connector. But
there is a 'high pedal lockout' circuitry which
prevents the controller taking off at high speed if the
throttle is faulty: this resets itself when the voltage on
pin E falls to zero.
So check that the throttle voltage varies from 0v
upwards. The top voltage may be 11.4 or less (the
gain can be adjusted to compensate) but never more
than 11.4v. This does not apply to the uncommon
Joystick mode where 'zero speed' is about 5.5v.
If the 12v is correct and the pot voltage is altering
from zero upwards there is a fault in the controller.
Most faults in the controller will need attention at the
factory as they require instruments and experience of
such high current circuitry which are not usually
available to electronic repair shops.
Dead or Loss of power
See page 12: "High pot lockout".
Most models include adjustable battery discharge
protection which cuts back the power when the
voltage in the controller drops too low. If this is set
too high for the battery voltage, it will inhibit
operation.
Undervoltage protection cannot tell the difference
between a flat battery and a poor connection or a bad
wire. If the battery wires are too long and thin they
will drop voltage - and this may result in a dramatic
loss of power as the protection cuts in.
This feature may then require the use of thicker
battery wire
Other faults
See our www site. There is a large service section.