Handle Heating System; Troubleshooting - Stihl MS 650 Manual

14.

Handle Heating System

14.1

Troubleshooting

The entire handle heating system is
maintenance-free and subject to
practically no wear. Faults in the
generator, heating elements and
wiring are generally caused by
mechanical damage.
There are two reasons for failures in
the heating system:
1. A break in the circuit due to a
faulty wire or component.
2. A short circuit resulting from
damage to the insulation.
: The heating element in the rear
handle may overheat and fail if it
is not bonded firmly in position,
i.e. completely flat (no creases).
Tracing the
cause of a fault
– Remove the handle molding –
b 10.1
: Push back the insulating tube
(arrow) on the pin and socket
connector of the wire between
the generator and rear handle
heating element.
94
: Separate the pin and socket
connector.
I
o
: Set the heater switch (1) to "#"
– Set the ohmmeter to "Ω".
– Set the Master Control lever
to "$"
– Clip one ohmmeter test lead to
the generator wire and the other
test lead to the rear handle
heating element wire.
All electrical components of the
handle heating system are
connected in series with the
ohmmeter.
If the system is in order, the
ohmmeter will show a reading of
about 10 Ω in measuring range "Ω".
1
If no reading is obtained, there is a
break in the circuit.
If the ohmmeter shows a very low
value, there is a short circuit in one
of the components.
In either case it is necessary to
check each component separately,
b 14.5.1.
The generator wire remains
disconnected from the heating
element during this check.
– After completing the test,
reconnect the wires and push the
insulating tube over the pin and
socket connector.
– Install the interlock lever and
handle molding – b 10.2
MS 650, MS 660