TROUBLE SHOOTING FOR MODEL A-11 SERIES
This trouble shooting guide should be used by trained service personnel or experienced electricians The guide is a step
by step procedure which can be followed in servicing the LaMarche model A-11 series of chargers
EQUIPMENT:
The only instrument required is a multi-scale volt-ohm meter, such as Simpson 260 or Triplette 630 Miscellaneous
electrical tools will also be required.
I.
GENERAL:
On servicing new equipment, before setting up any complicated testing or lumping to any conclusions, give the unit a
general inspection. Check the following
A.
Check DC output cables, connections, battery type, and number of cells m battery with nameplate rating
B.
Check nameplate specifications with customer's order, and the unit in accordance with the nameplate
C.
Check input connections, input voltage, and line breaker size in accordance with nameplate
D.
Loose connections, poor solder connections, broken wires, etc.
II.
GROUND OR SHORT CIRCUIT TEST:
A simple ohmmeter check can be performed to check the unit for a short to ground, primary to secondary breakdown,
AC-DC short, or DC ground Upon installation of a new unit, the above checks can be made before installing If a short
of this type is suspected on a unit in service, check as follows
A.
Disconnect AC input power to the unit Disconnect the DC battery from the charger
B.
Set ohmmeter scale on ohms scale RX100.
C.
Measure from one terminal of the input to one terminal of the output. Meter should not indicate If the meter
reads full scale deflection, this indicates an AC-DC short
Wires beneath terminal board may be shorting. On high DC output units, the DC terminals heat to a high degree if
the terminals are loose. AC wires should not be near the DC terminals. If an AC wire is lying hard against the
DC terminal, it is possible for the insulation on the AC wire to heat, melt, and to short against the DC terminal.
On shipping, an AC wire may rub against the DC lugs, terminals, etc., and cause a short. These problems may
be eliminated by very carefully inspecting the wiring to make certain the AC wires are not touching the DC wiring
If no wires are touching, then it is possible that the primary and secondary of the transformer or reactor is
shorted. Disconnect the secondary of the transformer from the diodes. Measure with ohmmeter from input
terminal to one of the isolated secondary leads. If there Is an ohmmeter indication, there is a insulation
breakdown between primary and secondary windings. The transformer should be replaced.
D. Check the input terminals to ground, and check the output terminals to ground If the meter indicates full scale
deflection, a wire is touching
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