INSTALLATION, OPERATING AND TROUBLESHOOTING INSTRUCTIONS FOR MODEL E12
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3. Open float/equalize
potentiometer
3. Check continuity of float/equalize
potentiometer with volt-ohmmeter.
An open circuit from its slider to the
control Pin 2 will cause low unit
output.
4. Shorted transistor on power stage AC7-(B1)(D1)
4. Remove power transistors
from heatsink and check with
ohmmeter. A shorted transistor will
cause low unit output.
Charger will not taper to finish
rate
1. Defective battery
1. Check for defective cells in battery.
2. Defective electronic panel
2. Jump center coil on saturable reactor
if unit runs low; problem may be
control panel.
3. Open float/equalize potent-
iometer or switch
3. Check continuity of float/equalize
potentiometer and float/equalize
switch. An open switch or
potentiometer may cause the unit to
run high than normal.
TROUBLESHOOTING AND DIODE REPLACEMENT
The silicon diode may be a source of trouble. The function of the diode is to allow the flow of current
through it in one direction only. If the polarity of the conducting current is reversed, the diode will block
the current flow. Thus, the diode has a low resistance to current flow in one direction, and a high
resistance to current flow in the other direction. Therefore, a simple ohmmeter may be used to test the
diode. The procedure for checking the silicon diode is as follows:
1.
Isolate one end of the diode by disconnecting the wires attached to the nipple (or pigtail) end of the diode (only one end of
the diode must be disconnected).
2.
Clip one lead of the ohmmeter to the nipple (or pigtail) lead of the diode. Clip the other ohmmeter lead to the aluminum
heatsink (if a portable multimeter is used, set the switches on ohms, DC and scale RX100).
3.
Note the ohmmeter reading, then reverse the leads to the diode. Again, note the ohmmeter reading. If the diode is good,
the meter will indicate a high resistance in one direction, and a low resistance with the leads reversed. If the diode is
shorted, the meter will read full scale, or "0" resistance with the leads in either direction. If the diode is "open", the
ohmmeter needle will not indicate or show infinite resistance, indicating an open circuit with the ohmmeter leads in either
direction.
4.
All diodes must be checked in the event that more than one diode is defective.
5.
If the diode is defective, remove the defective diode from the heatsink and replace with a new diode. When installing a new
diode, be sure to note if the old diode was insulated from the heatsink. If the diode should be insulated from the heatsink,
care should be taken so that the mica insulating washer is placed properly on each side of the heatsink with insulating
bushing between the diode mounting stud and the aluminum heatsink.
WHEN ORDERING REPLACEMENT PARTS, SCHEMATICS, OR REQUESTING SERVICE INFORMATION,
ALWAYS GIVE MODEL NUMBER, SERIAL NUMBER AND AC INPUT VOLTAGE.
BATTERY CELL TYPES AND VOLTAGES
The LaMarche Float Chargers are designed specifically to charge lead acid (L), valve regulated lead acid
(LR) or nickel cadmium (N) batteries. These chargers float the batteries at 2.17 Vpc (LA), 2.25 Vpc (LR),
1.4 Vpc (N). The equalizing charge setting for the batteries are 2.33 Vpc (L), 2.27 Vpc (LR) or 1.55 Vpc
(N). The potentiometer adjustment allows for a + 5% adjustment from the nominal float/equalize
voltages. The charger nameplate indicates the type of battery and the number of cells the charger is
designed to charge.
* It should be noted that for proper battery selection, the battery must be rated to deliver the load
current for the required discharge period. Amp-hour capacity ratings are usually dependent on the rate
of discharge. The battery manufacturer should be consulted to assure that these ratings will be valid for
the load currents, discharge times and any other salient conditions.
