Hitachi EX1900-6 Hydraulic Excavator Technical Manual – Operational Principle (TO18KE00) PDF Download

Description

Hitachi EX1900-6 Technical Manual – Operational Principle

This Hitachi EX1900-6 Technical Manual (Operational Principle) is the document that explains how every major system on the EX1900-6 hydraulic excavator works – from the Cummins QSK38-C engine and the six-pump hydraulic system to the swing, travel, and control circuits. Published under document number TO18KE00, this PDF is the operational theory companion to the Troubleshooting and Workshop manuals, and it is the reference you want when you need to understand not just what a component does, but how and why it does it.

Whether you run a fleet of EX1900-6 loading shovels and backhoes or you maintain a single machine, this manual gives you the system-level understanding that makes diagnosis and repair faster, safer, and more accurate. Every circuit, valve, pump, and controller is broken down with function descriptions, operational sequences, and cross-sectional illustrations.

File Details

• Manual Type: Technical Manual – Operational Principle
• Brand: Hitachi
• Model: EX1900-6 Hydraulic Excavator
• Document Number: TO18KE00
• Language: English
• Page Count: 269 pages
• File Format: PDF
• Engine Covered: Cummins QSK38-C (also referenced as QSKTA38-CE)

Chapters Covered

• Section 1 – General: Specifications, Component Layout, Component Specifications
• Section 2 – System: Controller, Control System, ELU System, Hydraulic System, Electrical System
• Section 3 – Component Operation: Pump Device, Swing Device, Control Valve, Control Equipment, DQR Valve, Travel Device, Others (Upperstructure), Others (Undercarriage)

Section 1 – General

The General section opens with full machine specifications for both the loader front and backhoe front configurations of the EX1900-6, including operating weight, bucket capacity, engine output, swing speed, travel speed, gradeability, and ground pressure. Dimensional data covers overall width, height, rear-end swing radius, undercarriage length and width, track shoe width, and more. Working range diagrams for the loading shovel and backhoe show digging reach, cutting height, dumping height, and digging depth. The component layout chapter maps every major assembly on the machine – from the bucket cylinder and swing device to the travel motor, center joint, and control valve – while the component specifications chapter details individual components including the engine, radiators, batteries, pumps, motors, valves, cylinders, and electrical sensors.

Section 2 – System

This is where the EX1900-6 operational principle manual earns its keep. The Controller chapter covers the MC (Main Controller), ELU (Electric Lever Control Unit), IDU (Information Display Unit), ECM (Engine Control Module), DLU (Data Logging Unit), CSU (Contamination Sensing Unit), and HMU (Hydraulic System Monitoring Unit), explaining how they communicate over CAN networks. The Control System chapter then walks through engine control, pump control (power increase, power decrease, and constant torque control), auto-lubrication control, oil cooler fan motor speed control, wiper control, and travel mode control – each with step-by-step operational sequences and circuit diagrams.

The ELU System chapter explains pilot shut-off control, positive pump control, cushion cylinder end travel regulation, and swing stop control. The Hydraulic System chapter covers the main circuit, pilot circuit, pump transmission oil cooling circuit, oil cooler fan motor circuit, air conditioner compressor motor circuit, and travel shock damper/travel stop circuit, including suction, delivery, return, single-operation, and combined-operation flow paths. The Electrical System chapter follows current from the battery through the key switch to the starter, charging circuit, engine stop circuit, and surge voltage prevention circuit, with fuse box layouts and relay logic.

Section 3 – Component Operation

The Component Operation section takes each major assembly apart – figuratively and literally – and explains its construction and working principle. The Pump Device chapter covers the pump transmission, main pumps (K3V180DTH19XL), 4-unit pump (K3V112S and KFP4156), and the regulators that control pump displacement angle through torque constant control, flow rate control, power decrease/increase control, and minimum flow rate signal priority control. The Swing Device chapter details the swing motor (MX750B0-10A), swing parking brake, two-stage planetary reduction gear, and valve unit with relief and make-up valves.

The Control Valve chapter breaks down the three main control valves (left, center, right), their spool arrangements, main relief valve, overload relief valves, and make-up valves. The Control Equipment chapter explains the electric lever, EHC valve (for electric lever control), and proportional solenoid valve operation. The DQR Valve chapter covers the Dual Quick Response valve construction and operation. The Travel Device chapter details the travel motor (MB750), travel mode control (slow/fast), brake valve (counterbalance and relief valve), parking brake, and two-stage planetary reduction gear. Finally, the Others chapters cover the air conditioner, auto-lubrication system, EHC valve (for main pump control), oil cooler fan motor, accumulator, swing bearing, adjuster cylinder, center joint, and more.

Who This Manual Is For

This Hitachi EX1900-6 technical manual is written for the field technician, the shop foreman, the maintenance planner, and the equipment owner who needs to understand the operational theory behind the machine’s systems. It is not a repair procedure manual – that is the Workshop Manual – but it is the essential companion to it. When you understand how the pump regulator responds to power increase and decrease signals, or how the DQR valve translates electric lever movement into pilot pressure, you diagnose faster and repair with confidence.

The manual’s operational sequences and cross-sectional illustrations also make it an excellent training resource for new technicians and operators who need to move beyond surface-level familiarity with the EX1900-6.

Why the Operational Principle Manual Matters

Heavy equipment diagnosis is rarely about finding a broken part – it is about understanding why a system is not behaving as designed. The EX1900-6 is a 190-ton-class hydraulic excavator with six main pumps, a Cummins QSK38-C engine producing 810 kW (1100 PS), and a control system that integrates electronic and hydraulic control in ways that demand system-level knowledge. This manual gives you that knowledge in plain, technically precise language, with circuit diagrams and cutaway views that show exactly what is happening inside each component.

If you are responsible for keeping an EX1900-6 loading shovel or backhoe productive, this manual belongs in your reference library.

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Instant PDF Delivery

This EX1900-6 Operational Principle manual is delivered as an instant PDF download. No shipping, no waiting, no physical media. After checkout, you can download the file immediately and open it on any device – laptop, tablet, or smartphone. The PDF is printable, so you can keep a paper copy in the shop or in the machine’s document compartment. Whether you need to reference the pump control circuit during a diagnostic session or study the swing device operation before a rebuild, the information is always at hand.