Belarus 80.1 Operation Manual page 369

7.13.3 Search for short circuit
One of the short circuit search methods is removal of the fuse and connection of a
tester-lamp or a voltmeter instead of it. There shall be no voltage in the circuit. Shake the
wire while looking at the tester-lamp. If the lamp starts blinking, there is a ground failure in
this cable, possibly caused by rubbing of wire isolation. A similar check can be carried out
for each of the circuit components including the switch of this circuit.
7.13.4 Check of availability of the electrical component "ground"
This check is carried out with the purpose of determining the availability of electrical
element safe "ground". Disengage AB "ground" disconnect switch and connect one of the
wires of the test lamp equipped with the self-contained power supply to the safe "ground".
The other lamp wire shall be connected to the cable or terminal which is being checked. If
the lamp lights up, grounding is normal (and vice versa). If the minus supply circuit of the
high-current consumer is under checking, it is required to use the test lamp with the power
not less than 21W because with the bad contact of the "ground", the high-current consum-
er will not operate, but the lamp with small power will still light up.
7.13.5 Check of electrical circuit breakage
This check is carried out with the purpose of determining electrical circuit break-ages.
After disconnection of circuit power supply, check it by means of a test lamp equipped with
a self-contained battery. Connect the test lamp wires to both ends of the circuit (or to the
power terminal (+) and to the safe able tractor "ground"); if the control lamp lights up it
means the circuit has no breakage. The lamp failure to turn on indicates that the circuit has
conductivity fault. The switch operability can be checked in a similar way by connecting the
test lamp to its terminals. As you turn the switch into "On" position, the control test lamp
shall light up. If the switch which is commutating power for a high-current consumer is un-
der check, it is also required to use the test lamp with the power not less than 21W. The
reason is that with the bad contact in the switch, a high-current consumer will fail to oper-
ate while the lamp with small power will still light up.
7.13.6 Breakage localization
While carrying out diagnostics of the circuit segment suspected of breakage, it is dif-
ficult to detect circuit breakage visually as inspection of terminals for presence of corrosion
or their defects in contact quality can be difficult due to limited access to them (as a rule
terminals are covered with the receptacle housing). In most cases, abrupt shaking of the
receptacle housing on the sensor or of the bundled cable leads to conductivity recovery.
Remember this when trying to localize the reason for failure of the circuit suspected of
breakage. Occasionally arising failures can be caused by terminals oxidation or defects in
contact quality.
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80-0000010B OM