Husqvarna 570 Workshop Manual page 22

Hand grips and carburettor heater, 575XPG
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.
Trouble shooting
Trouble shooting can be carried out with most
components 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 C. See fig. 10.
Clean the contacts C and D. See fig. 10.
Measure the resistance between point C and D.
The resistance for heating elements should be 0,8-1,0 ohms.
Replace the element if the values deviate.
Front hand grip with heating element
Measure the resistance in the front hand grip element
between points C 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 A and E. See fig. 10.
The ohmmeter should show 0,5 ohms.
If the value is higher, replace the generator.
Switch
Release one of the connections to the switch and
connect the ohmmeter between the points A and B.
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 and thermostat
The heating element and thermostat are in a single unit
and must be replaced together.
Release the earth cable G. Measure with the ohmmeter
between G and F.
The ohmmeter should show 0 at an air temperature of
15 C or higher. Cool the thermostat with a cooling spray
or the like.
The ohmmeter should show 8 A.
Replace the two elements if the values deviate.
Refit the relevant components.
22 – English
ELECTRICAL SYSTEM
E
G
Fig. 11
A
B
C
D
F