Komatsu BBX50 Series User manual

SERVICE MANUAL
ISSUED DECEMBER 2005
Read and observe all warnings on this unit
before operating it.
DO NOT operate this equipment unless all
factory installed guards and shields are
properly secured in place.
WARNING
BBX50 SERIES ELECTRIC FORKLIFT TRUCKS - S/N 090001A~
FB20/25/30/32SH-6
FB20/25/30/32SHE-6
FB20/25SHG-6
FB20/25SHGE-6
SM150
BBX50
Komatsu Forflift USA, Inc.

1
CONTENTS
Page No.
TABLE OF CONTENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . 1
INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . 5
APPLICABLE LIFT TRUCK MODELS COVERED IN THIS PUBLICATION .. . . . . . . . . . . . . . . . . . . . 6
CHAPTER 01 - SAFETY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .
Safety Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 01-1
Safe Travel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 01-5
Loading Operations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 01-13
Stopping and Parking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 01-19
Inspection and Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 01-20
Structure and Stability of the Lift Truck . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 01-26
CHAPTER 10 - GENERAL INFORMATION AND SPECIFICATIONS . . . . . . .. . . . . . . . . . . . . . . . . 10-1
Dimensions and Specifications (FB20SH-6 (36V & 48V)). . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 10-2
Dimensions and Specifications (FB20SHG-6 (36V & 48V)) . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 10-4
Dimensions and Specifications (FB25SH-6 (36V & 48V)). . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 10-6
Dimensions and Specifications (FB25SHG-6 (36V & 48V)) . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 10-8
Dimensions and Specifications (FB30SH-6 (36V & 48V)). . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 10-10
Dimensions and Specifications (FB32SH-6 (36V & 48V)). . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 10-12
Periodic Replacement of Consumable Parts . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 10-14
Standard Tightening Torque for Bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 10-15
Standard Tightening Torque for Pipe Joints . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 10-16
How to Use Loctite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 10-17
Conversion Tables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 10-18
CHAPTER 20 - TESTING AND ADJUSTING. . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 20-1
Service Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 20-2
Controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 20-3
Controller Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 20-3
Checking Controller Fans. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 20-3
Wiring of Type EE Truck. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 20-4
Location of Connectors & Terminals. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 20-5
Selecting Optional Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 20-6
Optional Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 20-7
Display Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 20-8
User Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 20-8
Service Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 20-10
Service Mode Adjustment Items. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 20-14
Details of Each Setting / Adjustment Item . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 20-15
Checking by Switch Monitor Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 20-18
Checking Switches (Sensors). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 20-19
Battery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 20-21
Fuses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 20-22
Traction AC Motor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 20-23
Assembling/Disassembling Procedures . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 20-25
Pump AC Motor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 20-26
Assembling/Disassembling Procedures . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 20-27
Temperature Sensor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 20-29
Temperature Sensor Replacement. . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 20-31

2
Speed Sensor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 20-32
Maintenance and Inspection of Motors. . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 20-33
Transfer Case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 20-34
Accelerator Pedal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 20-35
Brake Pedal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 20-37
Wheel Brake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 20-38
Parking Brake Lever - Adjusting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 20-39
Hydraulic Tank. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 20-40
Bleeding Air. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 20-41
CHAPTER 30 - REMOVAL AND INSTALLATION . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 30-1
Arrangement of Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 30-2
Weight of Each Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 30-3
Power Train (Front Axle - Transfer Case - Traction Motor). . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 30-5
Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 30-5
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 30-8
Rear Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 30-9
Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 30-9
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 30-10
Battery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 30-11
Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 30-11
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 30-12
Hydraulic Pump - Pump Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 30-13
Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 30-13
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 30-13
Controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 30-14
Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 30-14
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 30-14
CHAPTER 40 - DISASSEMBLY AND ASSEMBLY . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 40-1
Transfer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 40-2
Disassembly and Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 40-2
Differential. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 40-8
Disassembly and Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 40-8
Front Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 40-9
Disassembly and Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 40-9
Brake Master Cylinder. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 40-10
Disassembly and Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 40-10
Wheel Brake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 40-12
Disassembly and Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 40-12
Rear Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 40-13
Disassembly and Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 40-13
Lift Cylinder. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 40-16
Tilt Cylinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 40-16
Disassembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 40-17
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 40-17
Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 40-17
Hydraulic Pump. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 40-19
Disassembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 40-19
Seal Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 40-20
Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 40-21
Control Valve (Typical 3-Spool). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . 40-23
Disassembly and Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 40-24

3
Traction Motor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 40-25
Pump Motor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 40-26
Disassembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 40-27
Judging Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 40-28
Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 40-29
CHAPTER 50 - MAINTENANCE STANDARD . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 50-1
Transfer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 50-2
Differential. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 50-3
Front Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 50-4
Brake Master Cylinder. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 50-5
Wheel Brake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 50-6
Rear Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 50-7
Control Valve. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 50-9
Mast, Fork Carriage and Fork. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 50-10
Traction Motor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 50-11
Pump Motor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 50-12
Maintenance and Inspection of Motors. . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 50-13
CHAPTER 60 - STRUCTURE AND FUNCTION . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 60-1
Controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 60-2
Overview and Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 60-2
Outside View. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 60-2
Control Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 60-3
Hydraulic Control System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 60-3
Motor Speed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 60-4
Connection Diagram - Motor Power Circuits . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 60-4
Overview of AC Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 60-5
Overview of FET Power Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 60-6
Control Functions of Controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 60-7
Travel Interlock (Power Shutdown) . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 60-8
Load Handling Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 60-9
Lift Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 60-10
Travel Speed Limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 60-10
High Mast Tilt Speed Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 60-11
Seat Brake Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 60-12
FR-Related Power Steering Control Option. . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 60-12
Seat Switch Related Headlight Option. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 60-12
Protective Functions of Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 60-13
Thermal Cutback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 60-13
Overcurrent Protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 60-14
Low Voltage Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 60-14
Overvoltage Protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 60-14
Performance Characteristics Setup Function. . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 60-14
Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 60-15
Table of Character Displays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 60-28
CHAPTER 70 - TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 70-1
Preparation for Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 70-2
Before Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 70-2
Checking Battery Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 70-3
Checking Insulation Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . 70-3
Connector Terminals & Location of Controller . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 70-3
Failure Analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 70-4

4
Self-Diagnosis Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 70-4
Control Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 70-5
Classification of Error Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 70-6
Failure Analysis with No Error Code. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 70-7
Checking In-Line Fuses on Harness . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 70-8
Precautions for Cable Check & Voltage Measurement. . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 70-9
Checking Controller CPU PCB. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-10
Initialization of Adjustments / Settings . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-12
Precautions for Replacing CPU PCB . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-13
Pin Assignment of Connector on Truck Side Wire Harness . . . . . . . . .. . . . . . . . . . . . . . . . 70-14
Electric Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-16
Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-18
Controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-20
Overview and Features of Controller . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-20
Structure of Controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-20
Checking Electric Parts of Controller . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-24
Loose Parts and Poor Contact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-25
Checking On-Board Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-25
Removing CPU PCB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-25
Removing Power Supply PCB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-25
Connector Location and Pin Number of CPU PCBS . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-26
Connector Location and Pin Number of Power Supply PCB . . . . . . . .. . . . . . . . . . . . . . . . 70-28
Checking FET Power Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-29
Checking Main Fuse. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-31
Checking Main Contactor (MD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-32
Checking Capacitor PCBS (CD, CP) . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-32
Checking Current Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-33
Checking Cooling Fans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-34
Checking Resistors (R1/R2) for Fans. . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-34
Checking Resistor (RCH) for Capacitor PCB . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-34
Connector Voltage Checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-35
Controller System Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-42
Error Code List and Check Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-44
Motor (Traction and Pump) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-50
Problems and Corrective Actions. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-50
Control Valve. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-52
Trouble Diagnosis Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 70-52
CHAPTER 80 - YEARLY INSPECTION CRITERIA . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 80-1
Inspection Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 80-2
APPENDIX 1 - MAST SERVICE MANUALS . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .
E Series MD Masts - Full Free Lift 2-Stage. . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .
E Series MS Masts - Limited Free Lift 2-Stage. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .
E Series MT Masts - Full Free Lift 3-Stage. . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .

6
FORKLIFT TRUCKS
COVERED IN THIS PUBLICATION
BBX50 S/N 090001A~
KOMATSUMODEL
DESIGNATION DESCRIPTION
Electric Lift Trucks
FB20SH-6 4,000 lb. Capacity, Cushion Tire, High Option
FB20SHE-6 4,000 lb. Capacity, Cushion Tire, High Option, EE Rated
FB20SHG-6 4,000 lb. Capacity, Cushion Tire, High Option, Extended Frame
FB20SHGE-6 4,000 lb. Capacity, Cushion Tire, High Option, Extended Frame, EE Rated
FB25SH-6 5,000 lb. Capacity, Cushion Tire, High Option
FB25SHE-6 5,000 lb. Capacity, Cushion Tire, High Option, EE Rated
FB25SHG-6 5,000 lb. Capacity, Cushion Tire, High Option, Extended Frame
FB25SHGE-6 5,000 lb. Capacity, Cushion Tire, High Option, Extended Frame, EE Rated
FB30SH-6 6,000 lb. Capacity, Cushion Tire, High Option
FB30SHE-6 6,000 lb. Capacity, Cushion Tire, High Option, EE Rated
FB32SH-6 6,500 lb. Capacity, Cushion Tire, High Option
FB32SHE-6 6,500 lb. Capacity, Cushion Tire, High Option, EE Rated

SAFETY MANAGEMENT
1-1
SAFETY MANAGEMENT
• Read the instructions in this Manual and the Safety Labels attached to the various parts of the lift truck,
and make sure that you understand and follow them. If you do not understand or do not follow the
instructions, this will lead to improper operation which may lead to damage, personal injury or death.
• Be sure that you understand the proper method of using the lift truck and the procedure for carrying out
an inspection, and ensure that they are carried out safely.
• Read this Manual and the Safety Labels again from time to time. If the Operation and Maintenance
Manual or Safety Labels have been lost or become dirty and cannot be read, obtain replacements from
your Komatsu Forklift dealer and attach the Safety Labels in the specified positions.
OPERATION MANUAL AND SAFETY LABELS
• This lift truck should be operated only by qualified personnel. Be sure you have proper qualifications
before operating the lift truck.
• Using this lift truck without due care and attention may lead to injury or even death of you or others.
Be sure that you read this manual thoroughly and understand the explanations completely before you
use this lift truck or carry out maintenance on it.
• When you start to use this lift truck, be sure that you carry out ample practice so that you become
accustomed to each part of the equipment. Even when you have become accustomed to handling the lift
truck, always drive carefully and do not try to force the truck beyond its capacity. Failure to observe these
precautions may lead to serious personal injury or accident.
• For those operators who have recently obtained qualifications to operate lift trucks, always seek the
advice of experienced operators or instructors in the methods of operating and loading the lift truck.
• For those operating more than one lift truck, even if the model is the same specification, remember that
each truck differs slightly in the performance and reaction of the brakes, accelerator, and loading system.
When changing from one truck to another, always be sure that you become accustomed to the
performance of the truck before operating it. The feeling when operating the brakes is particularly
important.
• When operating this lift truck, even if you have experience in operating other lift trucks, obtain instruction
from an authorized person who has experience in operating this lift truck or the same type of lift truck.
OPERATION QUALIFICATIONS
• Avoid loose clothing, jewelry, and loose long hair. They can catch on
controls or in moving parts and cause serious injury or death.
• Always wear a hard hat and safety boots.
• Depending on the working conditions, wear other safety equipment
as well.
CLOTHING AND PERSONAL PROTECTIVE ITEMS

SAFETY MANAGEMENT
1-2
• Do not use this lift truck unless it is equipped with the overhead guard and load backrest shipped with the
lift truck from the factory by Komatsu Forklift.
OVERHEAD GUARD, LOAD BACKREST
• Any modification made without authorization from Komatsu Forklift can create hazards.
• Before making any modification whatsoever, consult your Komatsu Forklift dealer. Komatsu Forklift will
not be responsible for any damage, injury or death caused by any unauthorized modification.
• Do not install any equipment or parts which obstruct or limit the operator’s view.
UNAUTHORIZED MODIFICATION
• If any abnormality in the lift truck occurs, stop operation immediately, park
the lift truck in a safe place and safe condition, then contact the person in
charge.
• Be sure that fire extinguishers have been provided and that you read the
labels to ensure that you know how to use them.
• Know what to do in the event of a fire.
• Be sure that you know the phone numbers of persons you should contact in
case of an emergency.
• Provide a first aid kit at the storage point.
• Do not use the lift truck if it is leaking fuel. Inform the person on charge of the nature of the abnormality,
and repair the leakage before using the lift truck.
• Do not leave the lift truck with the engine running. Always apply the parking brake securely, lower the
forks to the ground, stop the engine, and remove the key before leaving the lift truck.
FIRE EXTINGUISHER AND FIRST AID KIT
• Do not operate the lift truck if you are fatigued, or when you have been drinking, or you have taken any
medication which can make you drowsy or sleepy.
• When carrying out operation, inspection, or maintenance of the lift truck, always follow all work shop
rules, safety regulations and precautions.
• During operation, always pay attention to safety and be careful of pedestrians, traffic and other
surrounding conditions.
SAFETY RULES
• The overhead guard is installed to protect the operator from falling objects. It is designed to withstand the
force of light boxes or small packages. It is not designed to withstand every possible impact.
• Always be careful to prevent damage or injury from falling objects.
SAFETY EQUIPMENT

SAFETY MANAGEMENT
1-3
• When reversing, depending on the situation, an optional alarm, reversing lamp or rotary lamp should be
used. In all cases, be sure to face the rear and check around before traveling in reverse.
CHECK WHEN TRAVELING IN REVERSE
• Do not travel on public roads unless you comply with local, state or other laws which regulate such
activity.
• Always observe all traffic regulations when operating the lift truck.
• Do not drive on public roads with the lift truck loaded.
• Do not tow other machines on public roads. (Do not tow other machines even when not on public roads).
• Always carry your driver's license when traveling on public roads.
TRAVELING REGULATIONS ON PUBLIC ROADS
The tire fenders prevent objects from being thrown up by the tires. When changing from a single tire to a
double tire arrangement on your forklift truck, always extend the tire fenders to cover the additional tires. If
the fenders are not extended, small stones and other objects will be thrown up and may injure the operator
or other people in the surrounding area.
TIRE FENDERS
• Always work on level surfaces and wipe up all oil or grease from the ground.
• When working on quays, platforms, docks or other places where there is a danger of falling, set up blocks
to prevent the lift truck from going over the edge.
• Put warning signs up in dangerous places to warn the operator not to approach.
• Mark the travel areas clearly and maintain the road surfaces in good condition.
• Put up signs to prevent unauthorized machines from entering areas where trucks are being operated.
• Ensure that there is adequate lighting to enable operations to be carried out safely.
SAFE WORKING AREA

SAFETY MANAGEMENT
1-4
• Keep the operator's compartment clean and tidy. Be sure to clean up all oil or mud. If the operator's hand
or foot slips, this may lead to a serious accident.
• Do not leave tools or spare parts lying around in the operator's compartment. They may damage or
obstruct the control levers or pedals. Always keep them in the tool box when not being used.
CLEAN OPERATOR'S COMPARTMENT
• Before operation, establish an operating plan and hold a meeting to discuss operating safety.
• In confined areas, position a signal person and carry out operations in accordance with his or her
instructions.
• When carrying out operations on roads, put up fences around the working area and carry out operations
in accordance with instructions from the signal person.
SAFE OPERATING PLAN
• The permissible load for any lift trucks equipped with an attachment is lower than the permissible load for
the standard lift truck. Reason:
1. The permissible load must be reduced by an amount equivalent to the weight of the attachment
itself.
2. Because of the thickness of the attachment, the load center moves forward.
• Always observe the permissible load as stated on the capacity plate (also called “nameplate”) strictly (this
plate is stuck to the lift truck or the attachment). Never exceed the permissible load.
REDUCE LOAD FOR LIFT TRUCKS WITH ATTACHMENT
• Avoid operating or leaving the lift truck outside in wet and rainy weather or snow and icy conditions.
• When washing the lift truck, use care to prevent water from contacting electrical parts. If water does come
in contact with the electrical system it may cause the system to operate abnormally and it may become
impossible to control the lift truck.
KEEP FREE FROM WATER
You must follow lockout or tagout procedures to control hazardous energy during the inspection, servicing
and maintenance operations of your lift truck as defined in the Occupational Health and Safety
Administration (OSHA) Standard 29 CFR 1910.147.
• When there are deficiencies or any mechanical defect that would prevent the safe operation of the truck:
1. Remove the lift truck from service and park it.
2. Initiate lockout or tagout procedures according to the safety policy in place in your facility until the
repairs are completed.
• When service personnel outside your facility are involved in the inspection, servicing and maintenance
operations of your lift truck:
1. Inform the outside employer of your lockout or tagout procedures. The outside employer must also
inform you of their procedures.
2. Ensure that your employees understand and comply with the restrictions and prohibitions of the out-
side employer's energy control program.
USE LOCKOUT OR TAGOUT PROCEDURES