Technician Service Guide 33367B
5
Measure and record the AC line voltage at the
charger power switch.
Connect the AC power plug to a live electrical outlet
with the proper AC voltage per charger nameplate
and, if equipped, voltage selector switch setting.
Locate the WHITE and BLACK AC power cord lead
connections to the power switch. Attach leads from
a suitable AC voltmeter to these AC cordset
connections and verify the presence of proper AC
voltage. If no voltage is measured, replace the AC
cordset with the replacement service part specified
on the parts list for this specific model charger and
retest.
Measure and record the AC line voltage at the
AC fuse(s) or circuit breaker(s).
If the presence of AC voltage on the cordset is
verified, move the AC voltmeter test leads to the
transformer side of the AC fuse(s) or circuit
breakers(s). Test points A and B on the service
wiring diagram. See figure 3.
Figure 3
If no AC voltage is measured on the transformer
side of the AC fuse(s) or circuit breaker(s), test
points A and B, remove the AC power plug from the
AC outlet. Test for continuity through the power
switch, AC voltage selector switch and AC
fuse(s)/fuseholder(s) or circuit breaker(s). Replace
all parts measuring no continuity with replacement
service part(s) specified on the parts list for this
specific model charger and retest.
If the correct AC voltage is measured on the
transformer side of the AC fuse(s) or circuit
breaker(s), proceed to
Section 3, Part B, Test for
correct transformer auxiliary coil voltage.
If the
transformer auxiliary coil test indicates a failed
transformer, test for correct charger indicator light
operation after transformer replacement. If the
transformer auxiliary coil test indicates proper AC
voltage output or the indicator lights still do not
illuminate after transformer replacement, the
electronic timer must be repaired or replaced.
Replace the electronic timer with the replacement
service part specified on the parts list for the specific
model of charger being serviced and confirm
indicator light illumination.
WARNING: ALWAYS TEST SCRs BEFORE
REPLACING AN ELECTRONIC TIMER. DAMAGE
AND SUBSEQUENT FAILURE WILL OCCUR TO
ALL ELECTRONIC TIMERS INSTALLED IN A
CHARGER THAT CONTAINS A SHORTED
ANODE TO GATE SCR, IF CONNECTED TO AC
POWER.
For SCR testing instructions see
Section 4, SCR
Testing Procedure.
Part B
Indicator lights illuminate but charger does not
produce output.
Charger models with an ammeter will show no
deflection, models without an ammeter but with a
fault light indicator may show an overvoltage fault
condition.
THIS MALFUNCTION SYMPTOM MAY BE DUE
TO FACTORS OTHER THAN THE CHARGER’S
PERFORMANCE. TO HELP ISOLATE THE
PROBLEM, IT IS OFTEN NECESSARY TO USE
THE CHARGER ON A DIFFERENT SET OF
BATTERIES AND THE ORIGINAL SET OF
BATTERIES ON ANOTHER CHARGER.
Test for battery voltage increase.
This condition may be caused by a high resistance
in the DC charging circuit due to a bad connection
or batteries. Using an appropriate DC voltmeter,
measure and record the DC voltage across the
batteries without the charger connected. Connect
the charger AC power plug to a live AC outlet and
the DC output plug to the equipment charging
receptacle. Note and record the initial voltage
increase measured.
Under normal operation the battery system voltage
will usually increase one or two volts when the
charger first turns on. After the initial increase the
battery voltage will gradually rise over time to it’s
final on-charge voltage. The final on-charge voltage
will vary depending on battery age, condition,
temperature and other factors. Conventional wet
lead-acid batteries will usually reach an on-charge
votlage of 2.5 volts per cell or higher, while sealed
batteries usually do not exceed 2.4 volts per cell.
