TM-5-2350-378-24-P
HYDRAULIC DIAGNOSTIC CENTER (HDC) SUPPORTING ARMORED COMBAT EARTHMOVER (ACE), M9
TECHNICAL MANUAL; UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL INCLUDING REPAIR PARTS AND SPECIAL TOOLS LIST
TM-5-2350-378-24-P - Page 18 of 790
TM 5--2350--378--24&P
0002 00--1
EQUIPMENT DESCRIPTION AND DATA
0002 00
EQUIPMENT CHARACTERISTICS, CAPABILITIES, AND FEATURES
The HDC is used to aid in troubleshooting the M9 ACE’s hydraulic system and components. The HDC consists of
a control box with a display screen, twenty electrically controlled solenoid valves, three manually controlled
valves, and thirteen transducers. Four wiring harnesses connect the HDC to the vehicle’s hydraulic system’s test
points (installed prior to use of the HDC, and left in place on the vehicle) and the LED screen. Each of the twenty
electronically--controlled valves (V1 through V20) return to their normal operating positions when the HDC control
box is shut off or power is disconnected for any other reason. Valves V1 through V20 can be opened and closed
by using the LINE UP and LINE DOWN buttons on the display screen to select a valve, then pressing the
CHANGE POSITION button to open or close the valve. The control box software allows up to four of the solenoid
valves to be powered ON at one time. Pressing the RESET VALVES button returns all valves to their normal
vehicle operating position (power OFF).
VALVE NO.
PWR
/
POSITION
V1
OFF
/
OPEN
V2
OFF
/
OPEN
V3
OFF
/
OPEN
V4
OFF
/
OPEN
V5
OFF
/
OPEN
V6
OFF
/
OPEN
V7
OFF
/
OPEN
V8
OFF
/
OPEN
V9
OFF
/
OPEN
V10
OFF
/
OPEN
V11
OFF
/
OPEN
V12
OFF
/
OPEN
V13
OFF
/
OPEN
V14
OFF
/
OPEN
V15
OFF
/
OPEN
V16
OFF
/
OPEN
V17
OFF
/
OPEN
V18
OFF
/
CLOSED
V19
OFF
/
CLOSED
V20
OFF
/
CLOSED
Valves V21 and V22, located in the bowl area near the high pressure filters, are manually operated and can be
operated from outside the bowl, while standing on top of the vehicle.
Valve V23, also manually operated, is located on the front of the directional control valve bank in the bowl area,
and must be operated while standing in the bowl. This valve is used to interrupt the flow to the ejector. It is rec-
ommended for safety purposes that the engine be shut down when operating valve V23.
The diagnostic unit is stowed in the driver’s compartment. It is removed and becomes mobile for use, and, upon
completion of troubleshooting, is stored in the driver’s compartment. Harness W4 is also stowed in the driver’s
compartment.
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