Possible Failures Of The Electrical Equipment And Instructions For Troubleshooting - Belarus 80.1 Operation Manual

7.13 Possible failures of the electrical equipment and instructions for trouble-
shooting
7.13.1 General information
Tractor BELARUS-80.1/82.1/820 electrical equipment includes electrical compo-
nents (switches, relays, electric motors, gauges, lamps, headlights, fuses, relay interrupt-
ers, sensors, etc.) as well as wires and electrical connections which serve for connection
of the components to power supply and the ground. To facilitate the task of troubleshoot-
ing in the electrical equipment, this manual contains an electrical connection diagram for
electrical equipment (Annex A, B, C).
Before starting operation on troubleshooting in any of electrical circuits, it is required to
study carefully the electrical diagram to familiarize yourself with the functional specifications of
the circuit. Search for a failure can be narrowed by gradual detection and exclusion of properly
functioning components of the same circuit. In case several electrical components fail to oper-
ate properly at the same time, the most probable reason for a failure can be burning-out of the
relevant fuse or the absence of "ground" (different electrical components in many cases may
have one fuse or the same "ground" terminal).
Electrical equipment failures can be explained by simple reasons like terminals cor-
rosion, faulty fuses, burning of the insert or a switching relay defect. Check visually the
condition of all fuses, wires and electrical connections of the circuit before starting the spe-
cific search for the components failures.
In case of using test instruments for detecting a failure, plan carefully in accordance
with the applied electrical diagram the points of the instrument connection to the circuit and
the succession of such connection, to detect the failure most effectively. The main test instru-
ments include a tester (multimeter) of electrical circuits, a voltmeter (a 12volt-pilot lamp (rated
21W) with a set of connection cables can also be used), an indicator of the circuit segment
conductivity (a test probe) which includes a lamp, electrical power supply and a set of connec-
tion cables.
Electrical circuit troubleshooting shall not be regarded as a complicated task when
taking into consideration the fact that current is supplied to all electrical components (lamp,
electric motor, etc.) in wires from AB through switches, relays, fuses, inserts, and then
goes back to AB through tractor "ground". Any problems related to the electrical equipment
failure may be caused either by termination of electrical current supply from AB or by ter-
mination of electrical current return to AB.
7.13.2 Check of voltage supply
Check of voltage supply shall be carried out in case of circuit malfunctioning. Connect
one of the tester wires either to the negative battery pole or to the tractor safe "ground".
The other tester wire shall be connected to the terminal of the circuit electrical connection,
preferably the one located nearer to the AB or to the fuse. If the pilot lamp on the tester
lights up, there is voltage on this circuit segment which proves circuit operability between
this terminal and the AB. Acting by analogy, inspect the rest part of the circuit. Detecting
absence of voltage supply indicates the failure between this circuit point and the last of the
checked before (where voltage supply was available). In most cases, the reason for mal-
functioning is loosening of electrical connections and poor contact quality. Remember that
power to some of the on-board electrical equipment circuits shall be sup-plied only in the
positions of starter and instruments switch "I" (instruments on) or "II" (starter on (unfixed
position)).
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