5: Maintenance
PRC-BC4-MS 5-7
Overcharge
Voltage
This section assumes a failure occurred during the “Overcharge Voltage
Check” procedure on page 5-3 if the overcharge voltage is not set at
14.0 VDC.
1. R1 (20 k ohm), R6 (100 k ohm) and R3 (330 k ohm) are 1% resistors
that set the overcharge voltage. Turn the PRC-BC4 off (remove the AC
power cable), and measure the resistance of these resistors to verify
they are within 5% of their stated value.
2. Turn the PRC-BC4 on and verify that the overcharge voltage is within
specification (it should be 14.0 VDC), refer to “Current Source” on
page 5-5 (step 8).
Undervoltage
Protection
This section assumes a failure occurred during the “Undervoltage Protection
Circuit Check” procedure on page 5-3 if the
FAULT LED does not light when
an undervoltage condition (possible shorted battery cell) exists.
1. Turn the PRC-BC4 on.
2. If no status LEDs are lit, refer to “Status LEDs” on page 5-8, also,
refer to “Current Source” on page 5-5 (step 5).
Reverse Current
Protection
This section assumes a failure occurred during the “Reverse Current
Protection” procedure on page 5-7 if diode D5 fails to provide reverse current
protection. Turn the PRC-BC4 off for the following checks.
1. On the DC input power line, measure the resistance across D5. If the
forward resistance is less than 10 ohms and the reverse resistance in
very high (mega ohms) the diode is okay; if not, replace the diode.
2. Measure the resistance from the DC input connector J5 pin B to PL7
pin 1. If it is not a dead short, check S6 and the associated wiring, also
refer to “AC Power Supply” on page 5-7.
AC Power Supply The section assumes a problem with the AC input power circuit. Turn the
PRC-BC4 off for the following checks.
CAUTION: Always turn the power off and remove the power
source before making any resistance measurements.
1. Visually inspect the AC and DC fuses. If either fuse is blown, skip to
step 4.
2. Measure the resistance across the thermostat S5. The thermostat is
closed until the chassis temperature reaches 75°C. Use a heat source to
open the thermostat; it should measure infinity when open and a dead
short when closed.
To Next Page
Loading...