TM 5-5420-280-23&P
0004 00
INTRODUCTION TO TROUBLESHOOTING (Contd)
i. Description of Hydraulic Control Valves Operation
KF1 Pressure switch on side of right lower support boom cylinder. When both cylinders are fully
extended, the switch closes and tells the SPS the cylinders are fully extended.
KF2 Pressure switch mounted on top of main hydraulic manifold. This switch is activated when the
lower support boom cylinders are fully retracted and subsequently tells the SPS.
KY1 Main control valve that supplies hydraulic pressure to hydraulic manifold. KY1 must be locked in
depressed position before manually operating all other control valves.
NOTE
Control valves KY2 and KY3 are no longer used and have been
removed.
KY4 Operates forward pin wheel drive to deploy lower bridge half.
KY5 Operates forward pin wheel drive to retrieve lower bridge half.
KY6 Operates rear pin wheel drive to deploy lower bridge half.
KY7 Operates rear pin wheel drive to retrieve lower bridge half.
KY8 Extends driver's side supporting cylinder to lift pallet.
KY9 Retracts driver's side supporting cylinder to lower pallet.
KY10 Extends passenger side supporting cylinder to lift pallet.
KY11 Retracts passenger side supporting cylinder to lower pallet.
KY12 Operates four transverse handling unit expanding cylinders to retract bridge quarters to
operating width.
KY13 Operates four transverse handling unit expanding cylinders to extend bridge quarters to
operating width.
KY14 Raises secondary boom.
KY15 Lowers secondary boom.
KY16 Lowers lower support boom.
KY17 Extends lower support boom.
KY18 Operates swivel drive to lower launch boom.
KY19 Operates swivel drive to raise launch boom.
KY20 Operates lower support boom in conjunction with KY17 to increase flow rate of hydraulic fluid.
KY21 Provides high pressure to winch motor to increase lifting capacity for play-in and pay-out of wire
rope as controlled by remote control unit (RCU) or winch emergency switch. Manually depressing
KY21 alone will not play-in or pay-out wire rope.
KY22 Provides low pressure to winch motor for play-in and pay-out of wire rope as controlled by RCU
or winch emergency switch. Manually depressing KY22 alone will not play-in or pay-out wire
rope.
KY23 Operates stop cylinder to hold bridge in place during coupling.
0004 00-8
