Lincoln Electric LF-72/74 User Manual

LF-72/74 SINGLE/DUAL

Section F-1

Section F-1

TABLE OF CONTENTS

- TROUBLESHOOTING & REPAIR SECTION -

Troubleshooting & Repair Section ........................................................................Section F

How to Use Troubleshooting Guide..............................................................................F-2

PC Board Troubleshooting Procedures and Replacement...........................................F-3

Troubleshooting Guide ..................................................................................................F-4

Test Procedures

Drive Motor and Tach Feedback Test..............................................................F-7/F-8

Gas Solenoid Test ..........................................................................................F-9/F-10

Diode Bridge Test ........................................................................................F-11/F-12

Wire Speed Potentiometer Test ...................................................................F-13/F-14

Replacement Procedures

PC Board Removal and Replacement.........................................................F-15/F-16

Wire Drive Motor and Gear Box Removal and Replacement......................F-17/F-20

Retest After Repair ...............................................................................................F-21