Description

Gehl Z80 Gen 2, Mustang 800Z Nxt 2 Compact Excavator Repair Service Manual

Language: English
Format: PDF
Applicable for the Gehl Excavator  Model Gehl Z80 Gen 2, Mustang 800Z Nxt 2

• Gehl Z80 Gen 2, Mustang 800Z Nxt 2 Excavator Repair Service Manual – 760 Pages
• Gehl Z80 Gen 2, Mustang 800Z Nxt 2 Excavator Operators Manual – 338 Pages
• Gehl Z80 Gen 2, Mustang 800Z Nxt 2 Excavator Parts Manual – 332 Pages

Table of Content of the Gehl Z80 Gen 2, Mustang 800Z Nxt 2 Excavator Manual:

CHAPTER 1
GENERAL CAUTIONS FOR MAINTENANCE WORK
1-1 Correct Work ………………………………………………………………………………………………………………………………………………………1-1
1-2 Safety Precautions ………………………………………………………………………………………………………………………………………………1-1
1-3 Preparations……………………………………………………………………………………………………………………………………………………….1-1
1-4 Cautions for Disassembly and Reassembly…………………………………………………………………………………………………………….1-1
1-5 Cautions for Removal and Installation of Hydraulic Equipment ………………………………………………………………………………….1-2
1-6 Cautions for Removal and Installation of Hydraulic Piping…………………………………………………………………………………………1-2
1-7 Cautions for Handling Seals………………………………………………………………………………………………………………………………….1-3
1-8 Correct Installation of Hydraulic Hose…………………………………………………………………………………………………………………….1-3
1-9 Specifications of Hydraulic Hose……………………………………………………………………………………………………………………………1-6
1-10 Air Release of Hydraulic Equipment……………………………………………………………………………………………………………………..1-8
CHAPTER 2
TECHNICAL DATA
2-1 Specifications …………………………………………………………………………………………………………………………………………………. 2-1-1
2-1-1 Standard arm type…………………………………………………………………………………………………………………………………… 2-1-1
2-2 Outline Drawing and Working Area……………………………………………………………………………………………………………………. 2-2-1
2-2-1 Standard arm type…………………………………………………………………………………………………………………………………… 2-2-1
2-3 Weight List of Main Parts …………………………………………………………………………………………………………………………………. 2-3-1
2-4 Lifting Capacity List …………………………………………………………………………………………………………………………………………. 2-4-1
2-4-1 Standard arm type…………………………………………………………………………………………………………………………………… 2-4-1
2-5 Specifications for Attachment……………………………………………………………………………………………………………………………. 2-5-1
2-6 Periodic Inspection and Servicing ……………………………………………………………………………………………………………………… 2-6-1
2-7 Fuel, Lube Oil and Grease Recommended…………………………………………………………………………………………………………. 2-7-1
2-8 Hydraulic Circuit Schematic ……………………………………………………………………………………………………………………………… 2-8-1
2-9 Wiring Diagram……………………………………………………………………………………………………………………………………………….. 2-9-1
CHAPTER 3
SERVICE STANDARDS
3-1 Machine Performance ……………………………………………………………………………………………………………………………………… 3-1-1
3-2 Engine …………………………………………………………………………………………………………………………………………………………… 3-2-1
3-3 Undercarriage ………………………………………………………………………………………………………………………………………………… 3-3-1
3-3-1 Rubber Crawler Specifications ………………………………………………………………………………………………………………….. 3-3-1
3-3-2 Common Specifications of Rubber Crawlers……………………………………………………………………………………………….. 3-3-2
3-4 Controls…………………………………………………………………………………………………………………………………………………………. 3-4-1
3-5 Hydraulic Equipment ……………………………………………………………………………………………………………………………………….. 3-5-1
3-5-1 Hydraulic Cylinders …………………………………………………………………………………………………………………………………. 3-5-1
3-6 Implement ……………………………………………………………………………………………………………………………………………………… 3-6-1
3-6-1 Front Attachments …………………………………………………………………………………………………………………………………… 3-6-1
3-6-2 Blade Moving Device……………………………………………………………………………………………………………………………….. 3-6-2
3-7 List of Tightening Torque …………………………………………………………………………………………………………………………………. 3-7-1
3-7-1 Machine…………………………………………………………………………………………………………………………………………………. 3-7-1
3-7-2 Engine …………………………………………………………………………………………………………………………………………………… 3-7-4
3-7-3 Tightening Torque for General Bolts and Nuts…………………………………………………………………………………………….. 3-7-5
3-7-4 Hydraulic Fitting………………………………………………………………………………………………………………………………………. 3-7-6
3-8 Pressure Adjustment……………………………………………………………………………………………………………………………………….. 3-8-1
3-8-1 Relief Valves ………………………………………………………………………………………………………………………………………….. 3-8-1
3-8-2 Swing Brake Valve ………………………………………………………………………………………………………………………………….. 3-8-3
3-8-3 Cut-off Valve…………………………………………………………………………………………………………………………………………… 3-8-4
CHAPTER 4
ENGINE
4-1 Safety ……………………………………………………………………………………………………………………………………………………………. 4-1-1
4-1-1 Safety Statements …………………………………………………………………………………………………………………………………… 4-1-1
4-1-2 Safety Precautions ………………………………………………………………………………………………………………………………….. 4-1-2
4-2 Engine …………………………………………………………………………………………………………………………………………………………… 4-2-1
4-2-1 Before You Begin Servicing ……………………………………………………………………………………………………………………… 4-2-1
4-2-2 Special Service Tools………………………………………………………………………………………………………………………………. 4-2-2
4-2-3 Measuring Instruments…………………………………………………………………………………………………………………………….. 4-2-5
4-2-4 Cylinder Head…………………………………………………………………………………………………………………………………………. 4-2-7
4-2-5 Measuring and Adjusting Valve Clearance ……………………………………………………………………………………………….. 4-2-22
4-2-6 Crankshaft and Camshaft Components ……………………………………………………………………………………………………. 4-2-24
4-2-7 EGR System…………………………………………………………………………………………………………………………………………. 4-2-50
4-3 Fuel System …………………………………………………………………………………………………………………………………………………… 4-3-1
4-3-1 Before You Begin Servicing ……………………………………………………………………………………………………………………… 4-3-1
4-3-2 System Structure…………………………………………………………………………………………………………………………………….. 4-3-2
4-3-3 Fuel System Diagram………………………………………………………………………………………………………………………………. 4-3-4
4-3-4 Fuel System Components ………………………………………………………………………………………………………………………… 4-3-5
4-4 Cooling System………………………………………………………………………………………………………………………………………………. 4-4-1
4-4-1 Before You Begin Servicing ……………………………………………………………………………………………………………………… 4-4-1
4-4-2 Introduction…………………………………………………………………………………………………………………………………………….. 4-4-2
4-4-3 Cooling System Diagram………………………………………………………………………………………………………………………….. 4-4-2
4-4-4 Engine Coolant Pump Components …………………………………………………………………………………………………………… 4-4-3
4-4-5 Engine Coolant System Check………………………………………………………………………………………………………………….. 4-4-4
4-4-6 Engine Coolant Pump ……………………………………………………………………………………………………………………………… 4-4-4
4-5 Lubrication System………………………………………………………………………………………………………………………………………….. 4-5-1
4-5-1 Before You Begin Servicing ……………………………………………………………………………………………………………………… 4-5-1
4-5-2 Introduction…………………………………………………………………………………………………………………………………………….. 4-5-1
4-5-3 Lubrication System Diagram …………………………………………………………………………………………………………………….. 4-5-2
4-5-4 Checking Engine Oil Pressure ………………………………………………………………………………………………………………….. 4-5-3
4-5-5 Trochoid Oil Pump…………………………………………………………………………………………………………………………………… 4-5-3
4-6 Starter Motor ………………………………………………………………………………………………………………………………………………….. 4-6-1
4-6-1 Before You Begin Servicing ……………………………………………………………………………………………………………………… 4-6-1
4-6-2 Introduction…………………………………………………………………………………………………………………………………………….. 4-6-1
4-6-3 Starter Motor Specifications ……………………………………………………………………………………………………………………… 4-6-2
4-6-4 Starter Motor Troubleshooting…………………………………………………………………………………………………………………… 4-6-3
4-6-5 Starter Motor Components ……………………………………………………………………………………………………………………….. 4-6-4
4-6-6 Starter Motor ………………………………………………………………………………………………………………………………………….. 4-6-5
4-7 Alternator……………………………………………………………………………………………………………………………………………………….. 4-7-1
4-7-1 Before You Begin Servicing ……………………………………………………………………………………………………………………… 4-7-1
4-7-2 Introduction…………………………………………………………………………………………………………………………………………….. 4-7-1
4-7-3 Alternator Specifications…………………………………………………………………………………………………………………………… 4-7-2
4-7-4 Alternator Troubleshooting ……………………………………………………………………………………………………………………….. 4-7-3
4-7-5 Alternator Components ……………………………………………………………………………………………………………………………. 4-7-4
4-7-6 Alternator Wiring Diagram ………………………………………………………………………………………………………………………… 4-7-5
4-7-7 Alternator Standard Output ………………………………………………………………………………………………………………………. 4-7-6
4-7-8 Alternator……………………………………………………………………………………………………………………………………………….. 4-7-7
4-8 Electronic Control System………………………………………………………………………………………………………………………………… 4-8-1
4-8-1 Before You Begin Servicing ……………………………………………………………………………………………………………………… 4-8-1
4-8-2 System Structure…………………………………………………………………………………………………………………………………….. 4-8-2
4-8-3 Electronic Engine Speed Control ………………………………………………………………………………………………………………. 4-8-3
4-8-4 Diesel Particulate Filter (DPF)…………………………………………………………………………………………………………………… 4-8-5
4-8-5 Troubleshooting of electronic control system ………………………………………………………………………………………………. 4-8-9
4-8-6 SMARTASSIST DIRECT (SA-D)……………………………………………………………………………………………………………… 4-8-11
4-8-7 Replacement of Components………………………………………………………………………………………………………………….. 4-8-12
4-8-8 Installation Position of Sensors ……………………………………………………………………………………………………………….. 4-8-15
4-9 Electric Wiring ………………………………………………………………………………………………………………………………………………… 4-9-1
4-9-1 Electric Wiring Precautions ………………………………………………………………………………………………………………………. 4-9-1
4-10 Failure Diagnosis ………………………………………………………………………………………………………………………………………… 4-10-1
4-10-1 Special Service Tools…………………………………………………………………………………………………………………………… 4-10-1
4-10-2 Tier 4 (BOSCH) Compression Inspection Procedures ………………………………………………………………………………. 4-10-2
4-10-3 Measured Value and Troubleshooting ……………………………………………………………………………………………………. 4-10-4
4-10-4 Quick Reference Table for Troubleshooting…………………………………………………………………………………………….. 4-10-4
CHAPTER 5
ELECTRIC SYSTEM
5-1 Electric Equipment of Machine………………………………………………………………………………………………………………………….. 5-1-1
5-1-1 Parts Layout of Electrical Equipment …………………………………………………………………………………………………………. 5-1-1
5-1-2 LCD Monitor and Alarm Systems …………………………………………………………………………………………………………….. 5-1-15
5-2 Circuit Description of Engine Start and Stop……………………………………………………………………………………………………….. 5-2-1
5-3 Engine ECU (engine controller)…………………………………………………………………………………………………………………………. 5-3-1
5-3-1 Outline …………………………………………………………………………………………………………………………………………………… 5-3-1
5-3-2 Control Functions ……………………………………………………………………………………………………………………………………. 5-3-3
5-4 Hydraulic ECU (Controller)……………………………………………………………………………………………………………………………….. 5-4-1
5-4-1 Outline …………………………………………………………………………………………………………………………………………………… 5-4-1
5-4-2 Engine Control………………………………………………………………………………………………………………………………………… 5-4-2
5-4-3 Speed Sensing Horsepower Limit Control ………………………………………………………………………………………………….. 5-4-8
5-5 Error Code……………………………………………………………………………………………………………………………………………………… 5-5-1
CHAPTER 6
HYDRAULIC SYSTEM
6-1 Outline…………………………………………………………………………………………………………………………………………………………… 6-1-1
6-1-1 Control Valve Operation …………………………………………………………………………………………………………………………… 6-1-3
6-1-2 Additional Operation of Control Valve ………………………………………………………………………………………………………… 6-1-4
6-2 Circuit Operation …………………………………………………………………………………………………………………………………………….. 6-2-1
6-2-1 Boom …………………………………………………………………………………………………………………………………………………….. 6-2-1
6-2-2 Arm……………………………………………………………………………………………………………………………………………………….. 6-2-3
6-2-3 Bucket …………………………………………………………………………………………………………………………………………………… 6-2-5
6-2-4 Swing…………………………………………………………………………………………………………………………………………………….. 6-2-6
6-2-5 Boom Swing …………………………………………………………………………………………………………………………………………… 6-2-7
6-2-6 Blade …………………………………………………………………………………………………………………………………………………….. 6-2-8
6-2-7 Travel ……………………………………………………………………………………………………………………………………………………. 6-2-9
6-2-8 Non-deviation Travel (with Boom, Arm, Bucket or Boom Swing Operation) …………………………………………………… 6-2-11
6-2-9 Simultaneous Operation of Boom Up and Arm Retract……………………………………………………………………………….. 6-2-12
6-2-10 Simultaneous Operation of Boom Up and Bucket…………………………………………………………………………………….. 6-2-13
6-2-11 Simultaneous Operation of Boom Up and Swing ……………………………………………………………………………………… 6-2-14
6-2-12 Simultaneous Operation of Arm and Bucket ……………………………………………………………………………………………. 6-2-15
6-2-13 Hydraulic P.T.O. …………………………………………………………………………………………………………………………………. 6-2-16
6-2-14 Travel Alarm ……………………………………………………………………………………………………………………………………….. 6-2-17
6-2-15 Auto Deceleration………………………………………………………………………………………………………………………………… 6-2-18
6-3 Hydraulic Pump………………………………………………………………………………………………………………………………………………. 6-3-1
6-3-1 Structure and Theory of Operation…………………………………………………………………………………………………………….. 6-3-1
6-3-2 Troubleshooting…………………………………………………………………………………………………………………………………….. 6-3-10
6-3-3 Disassembly and Reassembly ………………………………………………………………………………………………………………… 6-3-12
6-3-4 Service Standards …………………………………………………………………………………………………………………………………. 6-3-29
6-4 Control Valve………………………………………………………………………………………………………………………………………………….. 6-4-1
6-4-1 Main Control Valve ………………………………………………………………………………………………………………………………….. 6-4-1
6-4-2 Disassembly …………………………………………………………………………………………………………………………………………. 6-4-10
6-4-3 Cleaning ………………………………………………………………………………………………………………………………………………. 6-4-21
6-4-4 Checking ……………………………………………………………………………………………………………………………………………… 6-4-21
6-4-5 Reassembly………………………………………………………………………………………………………………………………………….. 6-4-21
6-4-6 Servicing Procedure for Relief Valve………………………………………………………………………………………………………… 6-4-26
6-4-7 Installation ……………………………………………………………………………………………………………………………………………. 6-4-30
6-4-8 Running ……………………………………………………………………………………………………………………………………………….. 6-4-30
6-4-9 Troubleshooting…………………………………………………………………………………………………………………………………….. 6-4-31
6-5 Pilot Valve ……………………………………………………………………………………………………………………………………………………… 6-5-1
6-5-1 Remote Control Valve ……………………………………………………………………………………………………………………………… 6-5-1
6-5-2 Travel Pilot Valve ………………………………………………………………………………………………………………………………….. 6-5-10
6-5-3 Blade and Boom Swing Pilot Valve ………………………………………………………………………………………………………….. 6-5-32
6-6 Swing Motor …………………………………………………………………………………………………………………………………………………… 6-6-1
6-6-1 Overview ……………………………………………………………………………………………………………………………………………….. 6-6-1
6-6-2 Description of Functions and Operation ……………………………………………………………………………………………………… 6-6-2
6-6-3 Precautions for Handling ………………………………………………………………………………………………………………………… 6-6-14
6-6-4 Troubleshooting…………………………………………………………………………………………………………………………………….. 6-6-15
6-6-5 Employment Tool ………………………………………………………………………………………………………………………………….. 6-6-21
6-6-6 Disassembly Procedure …………………………………………………………………………………………………………………………. 6-6-24
6-6-7 Assembly Procedure ……………………………………………………………………………………………………………………………… 6-6-37
6-6-8 Quality Check After Reassembly……………………………………………………………………………………………………………… 6-6-54
6-7 Travel Motor …………………………………………………………………………………………………………………………………………………… 6-7-1
6-7-1 Product Overview ……………………………………………………………………………………………………………………………………. 6-7-1
6-7-2 External Dimensions ……………………………………………………………………………………………………………………………….. 6-7-2
6-7-3 Basic Configuration and Drawing ………………………………………………………………………………………………………………. 6-7-3
6-7-4 Operating Description………………………………………………………………………………………………………………………………. 6-7-9
6-7-5 Troubleshooting…………………………………………………………………………………………………………………………………….. 6-7-22
6-7-6 Service outline………………………………………………………………………………………………………………………………………. 6-7-24
6-7-7 Disassembly …………………………………………………………………………………………………………………………………………. 6-7-31
6-7-8 Service Standard…………………………………………………………………………………………………………………………………… 6-7-49
6-7-9 Assembly……………………………………………………………………………………………………………………………………………… 6-7-51
6-7-10 Performance Confirmation Test …………………………………………………………………………………………………………….. 6-7-69
6-8 ESS Proportional Solenoid Valve………………………………………………………………………………………………………………………. 6-8-1
6-9 Cutoff Valve……………………………………………………………………………………………………………………………………………………. 6-9-1
6-10 Quick Coupler Solenoid Valve……………………………………………………………………………………………………………………….. 6-10-1
6-11 Pilot Check Valve (Quick Coupler) …………………………………………………………………………………………………………………. 6-11-1
CHAPTER 7
ADJUSTMENT AND REPAIR
7-1 Engine and Electric Equipment …………………………………………………………………………………………………………………………. 7-1-1
7-1-1 Removal and Reinstallation of Engine ……………………………………………………………………………………………………….. 7-1-1
7-1-2 Removal and Reinstallation of Starter Motor……………………………………………………………………………………………… 7-1-10
7-1-3 Removal and Reinstallation of Radiator and Oil cooler……………………………………………………………………………….. 7-1-11
7-1-4 Removal and Reinstallation of Fan Belt and Compressor Driving Belt ………………………………………………………….. 7-1-14
7-1-5 Removal and Reinstallation of Engine ECU………………………………………………………………………………………………. 7-1-15
7-1-6 Removal and Reinstallation of Hydraulic ECU …………………………………………………………………………………………… 7-1-17
7-1-7 Removal and Reinstallation of Diesel Particulate Filter (DPF) ……………………………………………………………………… 7-1-18
7-2 Undercarriage ………………………………………………………………………………………………………………………………………………… 7-2-1
7-2-1 Outline …………………………………………………………………………………………………………………………………………………… 7-2-1
7-2-2 Points of Reassembly (Rubber Crawler Type) …………………………………………………………………………………………….. 7-2-2
7-2-3 Removal and Reinstallation of Crawler ………………………………………………………………………………………………………. 7-2-3
7-2-4 Removal and Reinstallation of Travel Motor ……………………………………………………………………………………………….. 7-2-4
7-2-5 Disassembly and Reassembly of Idler ……………………………………………………………………………………………………….. 7-2-6
7-2-6 Disassembly and Reassembly of Track Roller…………………………………………………………………………………………….. 7-2-8
7-2-7 Disassembly and Reassembly of Carrier Roller…………………………………………………………………………………………. 7-2-10
7-2-8 Installation of Floating Seal …………………………………………………………………………………………………………………….. 7-2-12
7-2-9 Drawings of Jigs ……………………………………………………………………………………………………………………………………. 7-2-13
7-3 Controls…………………………………………………………………………………………………………………………………………………………. 7-3-1
7-3-1 Control Lever………………………………………………………………………………………………………………………………………….. 7-3-1
7-3-2 Travel Lever …………………………………………………………………………………………………………………………………………… 7-3-2
7-3-3 Adjustment of Lock Lever…………………………………………………………………………………………………………………………. 7-3-3
7-4 Swing Bearing ………………………………………………………………………………………………………………………………………………… 7-4-1
7-4-1 Removal and Reinstallation of Swing Bearing …………………………………………………………………………………………….. 7-4-1
7-5 Hydraulic Equipment ……………………………………………………………………………………………………………………………………….. 7-5-1
7-5-1 Removal and Reinstallation of Hydraulic Pump …………………………………………………………………………………………… 7-5-1
7-5-2 Removal and Reinstallation of Control Valve ………………………………………………………………………………………………. 7-5-5
7-5-3 Removal and Reinstallation of Remote Control Valves…………………………………………………………………………………. 7-5-7
7-5-4 Removal and Reinstallation of Blade Pilot Valve …………………………………………………………………………………………. 7-5-9
7-5-5 Removal and Reinstallation of Travel Pilot Valve……………………………………………………………………………………….. 7-5-10
7-5-6 Removal and Reinstallation of Boom Swing Pilot Valve ……………………………………………………………………………… 7-5-11
7-5-7 Removal and Reinstallation of Solenoid Valve…………………………………………………………………………………………… 7-5-12
7-5-8 Removal and Reinstallation of P.T.O. Solenoid Valve ………………………………………………………………………………… 7-5-13
7-5-9 Removal and Reinstallation of ESS Solenoid Valve …………………………………………………………………………………… 7-5-14
7-5-10 Removal and Reinstallation of Line Filter………………………………………………………………………………………………… 7-5-15
7-5-11 Removal and Reinstallation of Accumulator…………………………………………………………………………………………….. 7-5-16
7-5-12 Removal and Reinstallation of Swing Motor…………………………………………………………………………………………….. 7-5-17
7-5-13 Removal and Reinstallation of Swivel Joint……………………………………………………………………………………………… 7-5-19
7-5-14 Disassembly and Reassembly of Swivel Joint …………………………………………………………………………………………. 7-5-22
7-5-15 Disassembly and Reassembly of Hydraulic Cylinders ………………………………………………………………………………. 7-5-25
7-5-16 Hydraulic Oil Tank ……………………………………………………………………………………………………………………………….. 7-5-55
7-5-17 Piping Layout………………………………………………………………………………………………………………………………………. 7-5-59
7-6 Implement ……………………………………………………………………………………………………………………………………………………… 7-6-1
7-6-1 Removal and Reinstallation of Implement…………………………………………………………………………………………………… 7-6-1
7-6-2 Quick Coupler…………………………………………………………………………………………………………………………………………. 7-6-9
7-7 Cabin…………………………………………………………………………………………………………………………………………………………….. 7-7-1
7-7-1 Removal and Reinstallation of Cabin …………………………………………………………………………………………………………. 7-7-1
7-7-2 Disassembly and Reassembly of Cabin……………………………………………………………………………………………………… 7-7-3
7-7-3 Window/Door Glass Replacement Procedure……………………………………………………………………………………………. 7-7-17
7-8 Air Conditioner ……………………………………………………………………………………………………………………………………………….. 7-8-1
7-8-1 Removal and Reinstallation of Air Conditioner…………………………………………………………………………………………….. 7-8-1
CHAPTER 8
TROUBLESHOOTING
8-1 Non-breakdowns …………………………………………………………………………………………………………………………………………….. 8-1-1
8-1-1 Natural Release of Bucket………………………………………………………………………………………………………………………… 8-1-1
8-1-2 Discontinuous Arm Movement ………………………………………………………………………………………………………………….. 8-1-1
8-1-3 Thermal Shock of Travel Motor …………………………………………………………………………………………………………………. 8-1-2
8-1-4 Elongation of Boom Swing Cylinder on 60 degrees Swing ……………………………………………………………………………. 8-1-3
8-1-5 Time Lag on Travel Speed Switching…………………………………………………………………………………………………………. 8-1-4
8-1-6 Fluctuation in Oil Level of Hydraulic Oil Tank due to Temperature Change …………………………………………………….. 8-1-5
8-1-7 Operation of Quick Coupler Cylinder………………………………………………………………………………………………………….. 8-1-6
8-2 Quick Reference Table for Troubleshooting………………………………………………………………………………………………………… 8-2-1

This Service Manual is intended for Gehl Z80 Gen 2, Mustang 800Z Nxt 2 Excavator so as to give the owner/operator assistance in preparing, adjusting, maintaining and servicing the machine. More importantly, this manual provides an operating plan for safe and proper use of the machine. Major points of safe operation are
detailed in Chapter 2 – Safety. Read and understand the contents of this manual completely and become familiar with the machine before
attempting to operate it..

Throughout this manual, information is introduced by the word NOTE or IMPORTANT. Be sure to read the message carefully and comply with the message. Following this information will improve operating and maintenance efficiency, help to avoid breakdown and damage and extend the service life of the machine.