RedMax 967683802, Руководство по ремонту

Страница: 23 / 50

English – 23
Electrical system
9.3 Hand grip heater and
carburettor heater 385
Some chainsaws are fitted with hand grip heaters and
carburettor heaters, and consist of the following parts:
• Generator.
• Switch.
• Heating element in rear hand grip.
• Front hand grip with heating element.
• Carburettor heating element.
• Thermostat.
9.3.1 Trouble shooting
Trouble shooting can be carried out with most compo-
nents fitted on the saw. Trouble shooting requires:
• ammeter
• ohmmeter
• cooling spray.
The most common fault is oxidisation of the heating
element contacts in the rear hand grip and the switch
contact. Carry out trouble shooting as follows:
Heating element in rear hand grip.
Separate the cable connection at B. See fig. 10. Re-
move the switch with a screwdriver. See fig. 9. Set the
switch to position “0”.Clean the contacts D, E, F and G.
See fig. 10. Measure the resistance between point B
and F, between D and C and between E and C. See fig.
10. The resistance for both heating elements should be
0.6-2.4 ohms. Between D and C and between E and C
the resistance should be 0.3-1.2 ohms. Replace the ele-
ment if the values deviate.
Front hand grip with heating element
Measure the resistance in the front hand grip element
between points A and B. See fig. 10. The ohmmeter
should show 3-4 ohms. If the value is higher, replace
the hand grip.
Generator
Measure the resistance in the generator between the
points G and H. See fig. 10. The ohmmeter should show
0.3-1.3 ohms. If the value is higher, replace the genera-
tor.
Switch
Release one of the connections to the switch and con-
nect the ohmmeter between the points F and G. See fig.
10. The ohmmeter should show more than 1000 ohms
with the switch in position “0”. The ohmmeter should
show at least 0.1 ohms with the switch in position “1”.
Replace the switch if the values deviate.
Carburettor heating element
Measure the resistance for the heating element on the
carburettor at L and J. The ohmmeter should show 3-10
ohms. Replace the heating element if the value devi-
ates.
Thermostat
Release the earth cable J. Measure with the amme-
ter between J and K. Start the saw and run at approx.
10,000 rpm. The ammeter should show 0 at an air
temperature of 15 C or higher. Cool the thermostat with
a cooling spray or the like. The ammeter should show 2
A at 10,000 rpm. Replace the thermostat if the values
deviate. Refit the relevant components.
Fig. 9
Fig. 10
D
E
C
F
G
K
J
L
H
A
B