Lincoln Electric SVM151-A service manual CV Mode Output Control AT Maximum

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F-30

F-30

TROUBLESHOOTING & REPAIR

NORMAL OPEN CIRCUIT VOLTAGE WAVEFORM

CV MODE – OUTPUT CONTROL AT MAXIMUM

0 volts 0 volts

50V5µs

This is the typical CV output voltage generated from a properly operating machine. Note that each vertical division represents 50 volts and that each horizontal division represents 5 µs in time.

SCOPE SETTINGS

Volts/Div	50V/Div.
Horizontal Sweep	5 µs/Div.
Coupling	DC
Trigger	Internal

MULTI-WELD 350

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Contents Multi-Weld TM 350 Arc Converter Safety California Proposition 65 WarningsElectric 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 Table of Contents Installation Section Installation Technical Specifications MULTI-WELD 350 K1735-1Safety Precautions QUICK-CONNECT PIG-TAILSWork Connection Case GroundingFixed Parallel Operation Power Source Setup Converters Cable Size On Cable AWG mm2Table of Contents Operation Section Operation Safety InstructionsOperating Instructions Versatile Product DescriptionPortable Recommended Equipment and Processes MULTI-SYSTEM Power SourcePIG-TAIL Leads and Connectors Distribution BOXCC Mode Stick Welding and Gouging CV Mode Wire WeldingRemote Output Control Options Input Power/ Mode Switch has three positions Front Panel ControlsRecessed Panel Controls Transporting and Storage of the MULTI-WELD For CC STICK/GOUGE Mode onlyParalleled Converters Cable HandlingProtection Features MULTI-WELD Table of Contents Accessories Section Semiautomatic Welding Accessories AccessoriesOPTIONS/ACCESSORIES Connection of Lincoln Electric Wire FeedersTo Work MULTI-WELD Maintenance Section Table of ContentsSection D-1 Maintenance MaintenanceSee additional warning information throughout this manual Service Figure D.2 Major Component LocationsMULTI-WELD Table of Contents Theory of Operation Section Theory of Operation General DescriptionPower Modules and FEED- Back Figure E.3 Power Modules and FeedbackAnalog Control Power Supply Board and Weld Control Board Mode Selector and Output Controls Figure E.5 Mode Selector and Output ControlsOVER-VOLTAGE Protection Insulated Gate Bipolar Transistor Igbt Operation Pulse Width Modulation 8E-8Chopper Technology Fundamentals 70-80VDCMULTI-WELD Table of Contents Troubleshooting & Repair Section Troubleshooting & Repair HOW to USE Troubleshooting GuidePC Board Troubleshooting Procedures PC Board can be damaged by static electricityPerform the DC Buss Supply Troubleshooting GuidePower Supply Board Test Board TestCoil Resistance and Supply SpecificationsPerform the Input Contactor Voltage TestInput Voltage and Resistance TestFunction Problems Tion and Adjustment Test Analog Control Power Supply Board TestSee the Digital Meter Calibra Perform the DC Buss Supply Welding Problems Troubleshooting & Repair Troubleshooting & Repair Test Description Case Cover Assembly Removal Replacement ProcedureMaterials Needed Removal Procedure Replacement ProcedurePower Module Capacitor Discharge Procedure Procedure Figure F.2 Power Module Capacitor Terminal DischargeInput Contactor Coil Resistance and Supply Voltage Test Input Contactor Coil Resistance Supply Voltage Test Coil Test ProcedurePerform the Power Module Capacitor Discharge procedure Leads #303A #330Test for Contact Continuity Supply PC Board TestAnalog Control Power Supply PC Board Test Test Procedure Figure F.4 Analog Control Power Supply PC BoardPower Supply PC Board Test DC Buss Power Supply PC Board Test DC Buss Power Supply PC Board P46 P47Table F.2 DC Buss Power Supply PC Board Voltage Table Chopper PC Board Input Voltages and Resistance Test Figure F.6 Power Module Assembly Details Chopper PC Board Input Voltages Resistance TestTest Procedure for the Left Side Power Module Power Module Capacitor Discharge ProcedureScope Settings CC Mode Input Voltage Applied 75 VDCNormal Open Circuit Voltage Waveform CV Mode Output Control AT Maximum Machine Loaded to 350 Amps AT 34 Volts CC-STICK Mode Normal Weld Voltage WaveformMachine Loaded to 350 Amps AT 34 Volts CV Mode CV Mode Output Control AT Minimum Case Front Assembly Removal and Replacement DescriptionReplace the case cover Weld Control or Peripheral PC Board Removal and Replacement Figure F.8 Case Front Assembly Details Replacement Procedure Description Digital Meter Removal Procedure Lens Bezel Spacer Seal KnobOutput Control Potentiometer Removal Procedure Refer to Figure F.9Input Contactor Removal and Replacement Figure F.10 Input Contactor Assembly Details Lead #331Replacement Procedure Input Diode Removal and Replacement Figure F.11 Input Diode Assembly Details 25-27 300-324 Refer to Figure F.11FAN Motor Assembly Removal and Replacement Figure F.12 FAN Motor Assembly Details Perform the Input Diode Replacement procedure Perform the Input Diode Removal proce- durePower Capacitor Removal and Replacement Figure F.13 Power Capacitor Mounting Details Reassembly Chopper PC Board and Diode Module Removal and Replacement Chopper PC Board Removal and Replacement RemovalReplacement Refer to Figure F.14Diode Module Removal and Replacement Figure F.15 Diode Module Mounting DetailsRefer to Figure F.15 Figure F.16 Diode Module Tightening Sequence Open Circuit Voltages Retest After RepairIdle Amps Load TestElectrical Diagrams Table of Contents Electrical Diagrams SectionMULTI-WELD 350 Wiring Diagram Wiring Diagram MULTI-WELDSchematic Control PC Board #1 Schematic Control PC Board #2 Schematic Control PC Board #3 Schematic Control PC Board #4 Schematic Control PC Board #5 PC Board ASSEMBLY-CONTROL RESISTOR,SMD,1W,243OHMS,1%Schematic Peripheral Printed Circuit Board PC Board ASSEMBLY-PERIPHERAL PC Board Reference Description DesignatorsSchematic Power Printed Circuit Board PC Board ASSEMBLY-POWER Return to Section Return to Section TOC To Section TOCSchematic Analog Printed Circuit Board PC Board ASSEMBLY-ANALOG Schematic BY-PASS Printed Circuit Board PC Board Assembly BY-PASS Schematic Chopper Printed Circuit Board 19303 MPC Board Assembly Chopper SVM Error Reporting Form