Lincoln Electric SVM188-A service manual SCR Bridge Test

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F-29

TROUBLESHOOTING AND REPAIR

F-29

SCR BRIDGE TEST

WARNING

Service and repair should be performed by only Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or machine operator and will invalidate your factory warranty. 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 perform the test/repairs safely, contact the Lincoln Electric Service Department for electrical trou- bleshooting assistance before you proceed. Call 1-888-935-3877.

TEST DESCRIPTION

This procedure will aid the technician in testing of the SCRs in the output rectifier assem- bly by providing both a static and an active test for the devices.

MATERIALS NEEDED

Misc. Hand tools

Analog Multimeter

SCR Tester (Described in this procedure)

DC-600

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Contents DC-600 ISAFETYi Electric Shock can kill SafetyFumes and Gases Can be dangerousFor Electrically Powered equipmentSûreté Pour Soudage a L’Arc Précautions DE SûretéElectromagnetic Compatibility EMC Safety Master Table of Contents for ALL Sections Table of Contents Installation Section Technical Specifications DC-600 InstallationSafety Precautions Electric Shock can KillSelect Proper Location Fuse and Wire Sizes Electrical Input ConnectionsGround Connection Connection for Highest Rating Plate VOLTAGE, 50 or 60 HZ Reconnect ProcedureConnection for 440 Volts 50 or 60 HZ V 60HZ See Machine Rating Plate for Required Input Supply Voltage Output Connections ELECTRODE, Work and #21 LeadConnections Auxiliary Power Control Connections Terminal Strip 1 T.S.1Terminal Strip 2 T.S.2 DC-600 Table of Contents Operation Section Operation Safety PrecautionsDesign Features Advantages General DescriptionRecommended Processes and Equipment OFF Input Power Meanings of Graphical Symbols on Case FrontWelding Capability Output Control Output Voltage CurrentControls and Settings Meaning of Graphical Symbol for Ground CON- NectionOVERLOAD, OVERCURRENT, and Fault Protection Auxiliary Power in MS-RECEPTACLERemote Control of Machine Operation Welding Procedure RecommendationsOperating Steps Remote NA-3 Automatic Wire FeederLN-7 and Other Constant Wire Feeders LN-8 or LN-9 SEMI-AUTOMATIC Wire FeederDC-600 Table of Contents Accessories Section Wire Feeders and Tractors AccessoriesFactory or Field Installed Options Field Installed OptionsFigure C.2 MULTI-PROCESS Switch Cable Connections Accessories Table of Contents Maintenance Section Maintenance Safety Precautions Electric Shock can KillRoutine and Periodic Maintenance 1TABLE of CONTENTS-THEORY of Operation Section E-1 Input Circuit and Main TRANS- Former Theory of OperationFiring CIRCUIT, Control CIR- Cuit and Rectification RectificationFiring Board Thermal Protection SCR Operation DC-600 1TABLE of Contents Troubleshooting and Repair F-1 HOW to USE Troubleshooting Guide 2TROUBLESHOOTING and REPAIRF-2PC Board Troubleshooting Procedures Troubleshooting and RepairControl Feeder. See Protective Devices Check all three phase input Output Control J1,Pin2. See Wiring Diagram Wiring Diagram PC Board Troubleshooting Guide Test DescriptionMaterials Needed PC Board Troubleshooting Guide Figure F.2 Control Board LEDs Control BoardDC-600 Internal Trigger Circuit Test Internal Trigger Circuit Test Procedure75 76 Internal Trigger Circuit TestDC-600 Firing Board Test Firing Board Test Control Board Test Figure F.7 Control Board Control Board TestMain Transformer Voltage Test Figure F.8 Input Contactor and Reconnect Panel Main Transformer Voltage TestFigure F.9 Transformer Secondaries Main Transformer Voltage Test Control Transformer Test Control Transformer Test ProcedureInput Contactor Test Voltage Test Input Contactor TestSCR Bridge Test SCR Bridge Test Anode Cathode Remove Insulating PaintActive Test Scope Settings Maximum Output Setting no Load Minimum Output Setting no Load 35TROUBLESHOOTING and REPAIRF-35 2V/Div Volts DC-600 Input Contactor CR1 CLEANING/REPLACEMENT Input Contactor CLEANING/REPLACEMENT Procedure Cleaning ProcedureContactor Replacement Procedure SCR Rectifier Bridge Removal and Replacement Procedure Removal and Replacement Procedure 42TROUBLESHOOTING and REPAIRF-42Removal Procedure SCR Rectifier BridgeInsulator Lock Washer Plain Washer Output Snubber Lead Replacement ProcedureDC-600 Main Transformer and Choke Removal and Replacement Main Transformer and Choke Removal and ReplacementRemoval Procedure Weld Maximum Open Circuit Voltages Input Idle Amps and WattsDC-600 Table of Contents Diagram Section Electrical Diagrams Wiring Diagram 230/460/575 Volt Machines G3506-1 Schematic Complete Machine G3575 Schematic Control PC Board G3408-1 Control PC Board Assembly G3409-1 Schematic Firing PC Board G3741-1