Rectifier Diode Bridge Test | Lincoln Electric SVM144-B specs

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F-15

TROUBLESHOOTING & REPAIR

F-15

RECTIFIER DIODE BRIDGE TEST

WARNING

Service and repair should only be performed by Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in dan- ger to the technician or machine operator and will invalidate your factory war- ranty. For your safety and to avoid electrical shock, please observe all safety notes and precautions detailed throughout this manual.

If for any reason you do not understand the test procedures or are unable to per- form the test/repairs safely, contact the Lincoln Electric service department for technical troubleshooting assistance before you proceed. Call 1-888-935-3877.

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TEST DESCRIPTION

This test will determine if the correct voltages are being:

a.Applied to the diode bridge.

b.Supplied from diode bridge to the control PC board.

MATERIALS NEEDED

3/8 in. Nutdriver Volt-ohmmeter

POWER MIG 255 wiring diagrams (See Electrical Diagrams Section of this Manual)

POWER MIG 255

Image 53

Lincoln Electric SVM144-B service manual Rectifier Diode Bridge Test, Test Description, Materials Needed

Contents

Power MIG Safety Electric Shock can kill Welding Sparks can cause fire or explosion Safety Sûreté Pour Soudage a L’Arc Précautions DE Sûreté Master Table of Contents for ALL Sections Installation Section Table of Contents Technical Specifications Power MIG Installation Location Safety PrecautionsUncrating the Power MIG Power MIG Figure A.2 Triple Voltage Machine Input Connections Shielding GAS GUN and Cable Installation Section B Operation Section Fumes and Gases can be dangerous OPERATIONB-2 Product Description OperationWelding Capability Limitations Description of Controls Wire Reel Loading READI-REELS, SPOOLS, or Coils Procedure for Changing Drive and Idle Roll Sets Setting RUN-IN Speed on STAN- Dard Power MIG Feeder Feeding Wire ElectrodeIdle Roll Pressure Setting To Start the Welder Making a Weld Avoiding Wire Feeding Problems Input Line Voltage Protection FAN Control Section C Accessories Section Drive Roll Kits AccessoriesK363P READI-REEL Adapter Dual Cylinder Mounting KIT K1702-1 Operating Instructions For Timer KIT Spool GUN Adapter KIT Making a Weld with the Spool GUN, Spool GUN Installed Section D Maintenance Section GUN Tubes and Nozzles MaintenanceRoutine and Periodic Maintenance Figure D.1 Component Locations Liner Removal Replacement Contact TIP and GAS Nozzle Installation To open up the handle 5MAINTENANCED-5 Description English Size Metric Size Table D.2 Section E Theory of Operation Section Main Transformer Theory of OperationInput Line Voltage Feedback Control Output Rectification Figure E.4 Constant Voltage Output Constant Voltage Output Feedback Wire Drive Motor Overcurrent Protection Wire Feed Overload ProtectionThermal and Overload Protection Figure E.6 SCR Operation SCR Operation Power MIG Section F Troubleshooting & Repair Section HOW to USE Troubleshooting Guide Troubleshooting & Repair Workstations PC Board Troubleshooting Procedures Output Problems SCR Rectifier Rectifier Function Problems Wire Feeding Problems Welding Problems Welding Problems Test Description Main Transformer Test Main Transformer Test Test Procedure Figure F.1 Troubleshooting and Repair Materials Needed Rectifier Diode Bridge TestTest Description Rectifier Diode Bridge Testing 208R 206 28 VAC 209R Power MIG Static SCR Rectifier Assembly Test Static SCR Rectifier Assembly Test Active SCR Rectifier Assembly Test Power MIG Active SCR Rectifier Assembly Test Active SCR Rectifier Assembly Test Figure F.7 Location Leads X2 Open switch SW-1 Wire Drive Motor and Tachometer Feedback Test Wire Drive Motor and Tachometer Feedback Test 515B 206B 15 VDC 5J1 1J1 Test for Supply Voltage to Tachometer 555 206B To 3.5 VDC 6J1 1J1 Test for Feedback Voltage to Control Board Volts Normal Open Circuit Voltage Waveform Typical Output Voltage Waveform Machine Loaded Machine Loaded to 250 Amps AT 26 VDC Scope Settings Machine Loaded to 220 Amps AT 22 VDC Scope Settings Troubleshooting & Repair Typical SCR Gate Voltage Waveform Power MIG Description Control PC Board Removal and Replacement Procedure Control PC Board Removal and Replacement Procedure Figure F.11 Control Board Mounting Power MIG Wire Drive Assembly Removal and Replacement Procedure 41TROUBLESHOOTING & REPAIRF-41 Procedure Wire Drive Assembly Removal and Replacement TOC Power MIG SCR Output Rectifier Removal and Replacement Procedure SCR Output Rectifier Removal and Replacement Figure F.15 Right Heat Sink Lead Disconnection Power MIG Capacitor Bank Removal and Replacement Procedure Capacitor Bank Removal and Replacement Troubleshooting & Repair Main Transformer and Output Choke Removal and Replacement TOC Power MIG FAN Motor Assembly Removal and Replacement Procedure FAN Motor Assembly Removal and Replacement Wire Speed Range Troubleshooting and RepairRetest After Repair Open Circuit Voltage Power MIG Electrical Diagrams Section Wiring Diagram Entire Machine Code 10563 L10979 Power MIG 255 208/230V Wiring Diagram Entire Machine Code 10583 L10980 Power MIG 255 230/460/575V Wiring Diagram Entire Machine Code 10986 L11980 Power MIG 255 230/460/575 Wiring Diagram Entire Machine Code 10990 L11979 Power MIG 255 208/230 Control PC Board Schematic G3520-1D1 3521 Control PC Board Assembly G3521-1 Powermig Display PC Board Schematic L10951 Lincoln Electric CO Display PC Board Assembly L10952-1 24374 S Snubber PC Board Schematic S24374 00 ~.04 Snubber PC Board Assembly M19248-1 SVM Error Reporting Form