Belarus 2022.6 Operator's Manual page 217

6.15.2 Check of voltage supply
Check of voltage supply shall be carried out in case of circuit malfunctioning. Con-
nect one of the tester wires either to the negative battery terminal or to the tractor safe
"weight". The other tester wire shall be connected to the terminal of the circuit electrical
connection, preferably the one located nearer to the AB or the fuse. If the pilot lamp on the
tester lights up, there is voltage on this circuit segment which proves circuit operability be-
tween this terminal and AB. Acting analogically, inspect the rest part of the circuit. Detect-
ing absence of voltage supply indicates the failure between this circuit point and the last of
the checked before (where voltage supply was detected). In most case, the reason for
malfunctioning is weakening of electrical connections and contact quality break. Remem-
ber that voltage to some of the on-board electrical equipment circuits can be supplied only
in the positions of starter and instruments switch "I" (instruments on) or "II" (starter on
(unfixed position)).
6.15.3 Search for short circuit
One of the short circuit search methods is removal of the fuse and engagement of
the lamp-tester or a voltmeter instead of it. There shall be no voltage in the circuit. Shake
the wire looking at the lamp-tester. If the lamp starts blinking, there is short ground failure
in this cable, possibly caused by rubbing of wire isolation. A similar check can be carried
out for each of the circuit elements including the switch of this circuit.
6.15.4 Check of availability of the electrical element "load"
This check is carried out with the purpose of determining the availability of electrical
element safe "load". Disengage AB with the "load" switch and connect one of the wires of
the continuity test lamp equipped with the self-contained power supply to the safe "load".
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 continuity test lamp with
the power not less than 21V because with the bad contact of the "load", the consumer fails
to operate and the lamp with small power will light up.
6.15.5 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 continuity test
lamp equipped with a self-contained battery. Connect the continuity test lamp wires to both
sides of the circuit (or to the high-power end (+) and to the reliable tractor "load"), if the
control lamp lights up it means the circuit has no breakage. The lamp failure to switch on
indicates that the circuit has conductivity fault.
The switch operability can be checked in a similar way by connecting the continuity
test lamp to its terminals. While shifting the switch into the position "On", the control lamp
shall light up. In this case if the switch commutating supply for a high-current consumer is
under check, it is also required to use the continuity test lamp with the power not less than
21 kW. The reason is that with the bad contact in the switch, a high-current consumer fails
to operate and the lamp with small power will light up.
6.15.6 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 access limitation to them (as a rule
terminals are covered with the connection housing). Abrupt shaking of the connection
housing on the sensor or of the bundled cable leads to conductivity recovery in many cas-
es. 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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2022.6-0000010 OM