Case 788 / 788 Plus / 988 / 988 Plus Excavator Schematic Manual Set – 1999 (P/N Cre 7-80183GB)

The electrical diagrams, fault charts and hydraulic tests work together to trace the machines’ electrohydraulic controls. Match the crawler or wheeled configuration and the applicable electrical revision before selecting a circuit or test.

Coverage limits: Engine and mechanical drivetrain teardown procedures are outside this set’s scope. The separate large-format “Pocket” schematic sheets listed in the contents are not included in this PDF.

Searchable PDF and Diagram Detail

Text search and drawing labels: Text search is available across the technical sections. There are no embedded PDF bookmarks. Small wire numbers, connector pins and hydraulic port labels require zooming in dense diagrams.

One printable English PDF contains 364 pages, including the two pages of set front matter and 10 blank pages. The section totals above already include those blank pages.

Electrical Fault Charts and Hydraulic Adjustments

The following topics are selected coverage highlights. Other reference material includes hydraulic fitting cap charts and bucket and clamshell specification tables.

• Electrical schematics: Cabinet PCB layouts, fuse and relay identification, P10 instrument panel diagrams, harness connections and diagnostic-socket wiring.

• Powersensor electronics: LED fault-code charts for electric acceleration, load-sensing pressure, engine speed, temperature sensing, control panels and swing brake release.

• Acceleration adjustment: Step-by-step servo-motor linkage adjustment and calibration procedures, including old, new and low-emissions linkage arrangements.

• Hydraulic testing: Pressure-test locations, flowmeter connections, pump-output checks, LS valve settings, DRE4 regulation and relief-valve adjustments.

• Travel and wheeled systems: Crawler travel-control adjustment, wheeled speed-change diagnosis, Orbitrol steering checks, brake-pressure tests and stabilizer/blade flow checks.

• Chassis and service reference: Machine weights, CK/LC/CKE dimensions, P-series wheeled configurations, monoblock and articulated boom data, lubricant charts and standard fastener torques.

This set suits technicians familiar with excavator electrical and hydraulic systems who can interpret circuit diagrams and use pressure, flow and speed test equipment.

Powersensor Fault Tracing and Calibration

The fault charts connect reported symptoms with checks of wiring, connectors, sensors and actuators. For electric-acceleration code 02, the troubleshooting path distinguishes connector oxidation, harness damage, linkage geometry and servo-motor faults. Together with the pinouts, this provides a basis for checking the control circuit before choosing a component for repair or replacement.

The control-box section identifies the diagnostic LED and test socket. LED-code diagnosis is described without a dialogue console; the socket also supports console access for deeper diagnosis and machine parameters.

Linkage differences: Mechanical adjustment distinguishes the older centered gauge, the later offset gauge and low-emissions arrangements. The troubleshooting notes warn that mishandling the temporary fixed-speed servo linkage can damage the turbocharger.

Hydraulic Circuits, Travel and Wheeled Controls

Component-location views connect the circuit drawings with the machine’s test points. The hydraulic sections distinguish the 788 attachment/travel pump arrangement from the 988’s twin variable-displacement pump bodies and separate swing supply.

Factory procedures cover pilot pressure, static and dynamic LS checks, hydraulic power under load, attachment relief valves and swing brake release. The crawler section also gives complete travel-control adjustment methods using either measured flow or sprocket speed.

Wheeled equipment: Steering and braking coverage includes Orbitrol relief-valve checks, parking and service brake tests, travel-motor displacement change and stabilizer/blade adjustments. Combination-switch (“commodo”) diagrams show the connections for lighting, axle locking and associated controls, with country-specific circuit supplements.

Representative drawings include the Printed Circuit Schematic Guide, P10 Instrument Panel Electrical Schematic, X3 connector pin details, single- and two-speed crawler hydraulic circuits, and wheeled general hydraulic schematics.

Workshop Equipment and Safety

The tooling lists identify the Multi-Handi 2051 test kit E5444449, alternative test systems, flowmeter fittings and a control-spool spacer to manufacture. Electronic diagnosis also references the CAS 10449 photo-digital tachometer.

Before maintenance, consult the included safety precautions and hardware tightening instructions. The twin-wheel section addresses tire deflation and retaining-ring condition; hydraulic safety warnings cover stored pressure and supported attachments.

Examples from the Oil and Lubricant Tables

Engine oil sump capacities are 10 L for the 788/788 Plus and 14.3 L for the 988/988 Plus.

The hydraulic-fluid tables pair ISO VG 46 with ambient temperatures of -20°C to +40°C, ISO VG 100 with 0°C to +60°C, and ISO VG 22 with -40°C to +20°C. These recommendations accompany the specified CASE fluid requirements.