Lincoln Electric LF-72/74 service manual Replacement Procedures

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F-20	TROUBLESHOOTING AND REPAIR	F-20

WIRE DRIVE MOTOR AND GEAR BOX REMOVAL AND REPLACEMENT

PROCEDURE (Continued)

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REPLACEMENT PROCEDURES

1.Line up the gear box with the 4 holes on the panel. Replace and tighten the four 1/4-20 x 1/2 in. hex head bolts.

2.Insert the drive motor through the panel and gear box. Line up and tighten the three M6 x 1.00 in. Phillips pan head screws.

3.Replace the drive gear and secure in place using the screw and lock washer previously removed.

4.Replace the drive rolls and secure the secure locking rings.

5.Replace the gear box cover and secure with the 1/4-20 hex head screws.

6.Feed the gas hose, and the # 67 lead through the notch on the panel. Feed the P10 plug through the center panel. Align and mount and tighten the panel using the six lock washers and bolts previously removed.

7.Plug the P10 plug into the wiring harness.

8.Using the Phillips head screw driver connect the #67 electrode sense lead to the connector block.

9.Using the 3/4 in. wrench connect the electrode lead to the connector block.

10.Connect the gas hose.

11.Install the cover using the five screws.

12.Connect the gun.

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LF-72/74

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Contents LF-72/74 Safety Electric Shock can kill Welding Sparks can cause fire or explosion IiiPrécautions DE Sûreté Sûreté Pour Soudage a L’ArcMaster Table of Contents for ALL Sections Section A-1 Table of ContentsInstallation Section Installation Amp Rating Duty CycleMounting Safety PrecautionLocation Bench Mount Swivel MountBoom Mount SuspendedWeld Cable Sizes Coaxial Weld Cables Weld Cable ConnectionControl Cable Connections INSTALLATIONA-7Analog Control Cable Pin Function Miller Power Source Lincoln Wire FeederAnalog Miller Control Cable Adapter K2335-1 Wire Drive Systems Welding GUN/WIRE Feeder Trigger ConnectorRemote Sense Lead Specifications High Frequency ProtectionWelding GUNS, Torches and ACCES- Sories Magnum GUN and Cable AssembliesRolls.FIGURE A.4 Procedure for Changing Drive and Idle Roll SetsWire Drive Configuration Set the pressure arm as follows See Figure A.6 Pressure ARM AdjustmentGun Receiver For use With Bushing Wire Reel Loading Weld Wire Routing Figure A.9Shielding GAS Connection Installing Electrode To install Lincoln conduit See Figure A.10bConduit Kits For Codes 11209, 11210, 11211 and aboveAluminum Wire Preparations Figure A.12bINSTALLATIONA-18 Base Model Bench Model Standard Duty Bench Model Heavy DutyTypical System Configurations CableLF-72/74 Operation Section Section B-1Operation GAS Input Work ConnectionRecommended Processes Common Welding AbbreviationsProduct Description Front Panel Controls and Connections Figure B.1 Case Front Controls DescriptionBurnback and Postflow Timer KIT Cold FEED/GAS Purge SwitchStep Trigger Interlock Switch Remote Voltage Control KITWire Feed Speed Knob Trigger Connector 5-PIN AmphenolGUN Receiver Bushing K1500-2 Trigger InterlockAccessories Section Section C-1Accessories Optional KitsLF-72s Accessories Key LF-72/74 Maintenance Section Section D-1Maintenance MaintenanceCalibration Specification Routine MaintenanceFigure D.1 Figure D.3 Major Component Location Section AA-1 Section AAModel WFS Range Wire SizesAA-2 AA-3 Figure AA.1AA-4 AA-5 AA-6 Coaxial Weld CableK1797-xx INSTALLATIONAA-7AA-7 AA-8 Drive Roll Kits Steel or Cored Wires AA-9AA-10 Figure AA.3AA-11 Changing the Gun Receiver BushingLation or changing drive rolls and/or GuidesAssembly of Drive Rolls and Wire Guides AA-12AA-13 Set the pressure arm as follows See Figure AA.8AA-14 AA-15 Loading 16 to 44 lb .3 20kg Spools See figure AA.8AA-16 Figure AA.11AA-17 Figure AA.12aAA-18 Figure AA.12bAA-19 AA-20INSTALLATIONAA-20 Common Equipment SET-UPSFigure AA.15 High Volume Production AA-21Figure AA.16 Portable Welding AA-22Section BB-1 Section BBBB-2 Fcaw Innershield or OutershieldRequired Equipment BB-3BB-4 Figure BB.1 Case Front Controls DescriptionK2426-3 model BB-5K2426-1 and K2426-2 models Switch BB-6Section CC-1 CC-2 CC-3 CC-4 CC-5 CC-6 Section DD-1 Section DDTo verify the wire feed speed Nal wiringWhen inching with gun trigger, electrode WFS knob setting Could remain energized Several secondsMAINTENANCEDD-3 DD-3Figure DD.3 Major Component Location DD-4Theory of Operation Section Section E-1Theory of Operation Return to SectionControl Board LF-72/74 Troubleshooting & Repair Section Section F-1Troubleshooting & Repair HOW to USE Troubleshooting GuidePC Board Troubleshooting Procedures Function Problems Function Problems Troubleshooting & Repair Drive Motor and Tach Feedback Test Test DescriptionTest Procedure Troubleshooting and Repair GAS Solenoid TestTest Procedure Figure F.3 Leads 552, 552BDiode Bridge Test 552B + 552A Wire Speed Potentiometer Test Wire Speed Potentiometer Test 14F-14PC Board Removal and Replacement Control PC Board Removal and Replacement Procedure Removal Procedure Replacement Procedure Troubleshooting and Repair Wire Drive Motor and Gear BOX Removal and Replacement ProcedureProcedure Replacement Procedures SET UP Operation VerificationLF-72/74 Electrical Diagrams Section Section G-1Electrical Diagrams LF-72/74Timer KIT Board Normal Speed Micro Internal panel Motor Connecter Summary High Torque Setting engages Schematic Common Analog Control PC Board G4559 Sheet Electrical Diagrams Electrical Diagrams PC Board Assembly Common Analog Control G4560-2E0