INSTRUCTION / TROUBLESHOOTING MANUAL FOR MODEL A70B
PAGE 11 OF 16
A70B TROUBLESHOOTING
INSTRUCTIONS
Before troubleshooting unit, check for shipping damage. (i.e. broken wires, loose connections, etc.)
Quick-Check A70B Trouble Analysis
Problem: Blown AC input fuse.
1.
Check AC input voltage with tap setting on power transformer and control transformer. If AC input
and tap setting agree, see step #2.
2.
Check AC input current draw after replacing blown AC fuse. NOTE: If AC fuse clears as soon as
the AC contactor pulls in, go to STEP #5. On three (3) phase units, if the AC current is not
approximately equal, check the AC voltage input to the S2A-123 printed circuit board. Connector
#1, 4-5, 5-6, 6-4 should be 30 Vac. - 60 Vac. If this voltage is not there, retrace the wiring back to
the SCR/Diode modules. If voltage is there, continue to step #3.
3.
Check the AC voltage output on the S2A-123 printed circuit board, Connector #2, 4-1, 4-2, 4-3.
Voltages must be approximately equal or greater than 5 Vac. If it is not greater than 5 Vac.,
replace the S2A-123 printed circuit board.
4.
Connect charger to discharged battery, check output voltage and voltage across charger shunt bar.
If output voltage is below 2.3 Vpc., the voltage across shunt must not exceed 97mV. If it is over
97mV, adjust P4 on the S2A-122A printed circuit board counterclockwise which lowers the output
until 97mV across the shunt bar is indicated.
5.
If AC input fuse clears when the AC contactor pulls in make sure the correct AC fuses are being
used, time delay fuses. If the correct AC fuses are being used, disconnect J3 connector from the
S2A-122A printed circuit board.
6.
Replace blown AC fuse, turn on AC power. (If fuse is good, defective S2A-122A p.c. board.) If fuse
still clears, problem is a shorted SCR/Diode module or power transformer.
7.
Separate secondary leads from P.T. to SCR/Diode modules. If fuse still clears, problem is in the
(P.T.) power transformer. If fuse is good, problem could be in the SCR/Diode module.
SEE SCR/DIODE TROUBLESHOOTING GUIDE.
NOTE: Blown printed circuit boards, fuses or loose printed circuit boards fuses could cause an out of phase
condition. (Blowing AC input fuses) If a blown printed circuit board fuse is found, a wire on the gate lead of
the SCR/Diode module could be disconnected or a defective SCR/Diode module could exist.
Problem: Blown DC fuse.
1.
Make sure the correct type of fuse is being used.
2.
Check all connections to DC fuse to be certain they are tight.
3.
Check polarity of output cables, output connector, SCR/Diodes module and diode SD4 for shorts.
Problem: Blown control transformer fuse CTF1.
1.
Defective contactor (shorted coil)
2.
Control taps set wrong on control transformer.
3.
Defective control transformer.
