TM 5-5420-280-23&P
0008 00
Electrical System Troubleshooting (Contd).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
NOTE
Refer to launching and retrieval procedures in TM 5-5420-280-10
for operation of RCU.
Check that hydraulic system has pressure before performing
electrical troubleshooting. Refer to Hydraulic System
Troubleshooting (WP 0010 00).
Refer to Electrical System Schematic (WP 0122 00) when
performing troubleshooting malfunctions.
2. RCU WILL NOT POWER UP USING CBT
Step 1. Check that power cable is properly connected between CBT and bridge pallet.
If power cable is not properly connected, connect power cable between CBT and bridge
pallet. Refer to TM 5-5420-280-10.
Step 2. Check that all four emergency stops are in the OUT position.
a. Disengage emergency stops. Refer to TM 5-5420-280-10.
b. Replace emergency stop if damaged. Refer to WP 0049 00, WP 0050 01, and WP 0052 00.
c. Check operation of IQAN-XP and IQAN-XS LED lights. Refer to WP 0004 00 step h.
d. Check circuit breaker FI for 24 volts and reset or replace as necessary. Refer to
Step 3. Check for 24 volts at CBT power cable source.
Repair or replace CBT power cable or connection. Refer to TM 9-2320-435-10 or
TM 9-2320-425-10.
Step 4. Check for 24 volts at end of RCU cable connector.
a. If RCU cable connector has voltage, repair or replace RCU box. Refer to WP 0050 00.
b. If RCU cable connector has no voltage, perform step 5.
Step 5. Check for 24 volts at RCU receptacle on electrical box.
a. If electrical box RCU receptacle has voltage, repair or replace jumper cable between
electrical box and RCU stowage box. Refer to WP 0051 00.
b. If electrical box RCU receptacle has no voltage, repair or replace electrical connector
(WP 0051 00) or wires. Refer to Electrical System Schematic WP 0122 00 for wiring.
END OF TESTING
3. RCU WILL NOT OPERATE HYDRAULIC SYSTEM USING LPU OR CBT BATTERIES
Step 1. Check that hydraulic system has pressure.
Refer to malfunctions 1 or 2 in Hydraulic System Troubleshooting (WP 0010 00).
NOTE
KY1 is the main pressure hydraulic control valve solenoid and it
must operate with all other control valve solenoids to perform an
operation.
Step 2. Check that KY1 hydraulic control valve solenoid has 24 volts or the LED light is lit.
a. If light is lit and system will not operate, replace solenoid or hydraulic control valve.
Refer to WP 0075 00.
b. If light is out, check for 24 volts at control valve solenoid connector.
c. If connector has no voltage, check wire at KL-1 buss bar pin 1 for KY1 control valve
solenoid. Refer to Electrical System Schematic (WP 0122 00) repair or replace wires
d. Check operation of IQAN-XP and IQAN-XS LED lights. Refer to WP 0004 00 step h.
e. Check wire between KL-1 buss bar pin 1 and IQAN-XS connector pin 20. Replace wire
if damaged. Refer to WP 0053 00.
END OF TESTING
Change 1