TM 5-5420-280-23&P
0010 00
Hydraulic System Troubleshooting (Contd).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
5. WINCH WIRE ROPE WILL NOT OPERATE (L3-A) OR (R18-H)
NOTE
KY1, KY21 high pressure, and KY22 lower pressure control valve
solenoids retract (pay-in) winch wire rope, and KY1, KY21, and
KY22 control valve solenoids lower (pay-out) winch wire rope.
KY1 and KY21 are used to retract (pay-in) or lower (pay-out) winch
wire rope with a load on rope and KY1 and KY22 are used to
retract (pay-in) or lower (pay-out) winch wire rope without a load.
Step 1. Check that KY1, KY21, and KY22 hydraulic control valve solenoid LED lights are lit when
action button 1 (launch) or action button 2 (retrieval) is depressed.
NOTE
Limit switch KA5 stops winch cable when upper bridge half is
lifted to its up position.
If all lights are lit on control valve solenoids, check limit switch KA5 to see if damaged or
out of adjustment. Adjust or replace limit switch KA5. Refer to WP 0056 00.
Step 2. Check for damaged control valve KY1, KY21, or KY22.
If control valve will not operate, replace control valve. Refer to WP 0075 00.
Step 3. Check that winch system is operating electrically.
Refer to malfunction 6 Electrical System Troubleshooting (WP 0008 00).
Step 4. Check that winch control block has hydraulic pressure to operate system.
Refer to Winch Control Block Hydraulic Schematic (WP 0123 00).
Step 5. Check that load is not too heavy for system operation.
a. Operate in Limited Load position or reduce load on winch wire rope.
b. Operating oil temperature to high, let winch cool down.
Step 6. Check if wire rope slipping on winch pulleys.
a. Clean wire rope and check if worn.
b. If worn or damaged, replace winch wire rope. Refer to WP 0057 00.
Step 7. Check if winch hydraulic motor is operating.
If winch hydraulic motor has hydraulic pressure and will not operate, replace winch
hydraulic motor. Refer to WP 0068 00.
Step 8. Check if force transmitter is loose or damaged.
If force transmitter is loose or damaged this will stop winch from operating. Repair or
replace force transmitter. Refer to WP 0064 00.
END OF TESTING
6. BOTTOM BRIDGE HALF WILL NOT MOVE TO REAR (L5-A) OR (R17-H)
Step 1. Check for damaged or missing launch beam pin wheel drive bracket or drive pins.
a. If damaged or missing, replace pin wheel drive bracket. Refer to WP 0028 00.
b. If damaged or missing, replace drive pins. Refer to WP 0028 00.
Step 2. Check that KY1, KY4, and KY23 hydraulic control valve solenoid LED lights are lit when
action button 1 is depressed.
NOTE
Limit switch KA2 switches front pin wheel drive to rear pin wheel
drive during launch and switches rear pin wheel drive to front pin
wheel drive during retrieval.
