Lincoln Electric SVM151-A service manual Test for Contact Continuity, Supply PC Board Test

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F-19

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TROUBLESHOOTING & REPAIR

INPUT CONTACTOR COIL RESISTANCE AND

SUPPLY VOLTAGE TEST (CONTINUED)

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WARNING

ELECTRIC SHOCK can kill.

With the input power ON, there are high volt- ages inside the machine. Do not reach into the machine or touch any internal part of the machine while power is on.

9.Carefully apply the correct input power to the Multi-Weld 350 (50 – 113 VDC).

10.Set the Multi-Weld 350 to either CC or CV mode. The contactor should activate. If it does not, increase the input voltage but do not exceed 113 VDC.

11.Carefully check for approximately 40 VDC at leads #303A to #330. If the 40 VDC is applied to the coil leads, the contactor should activate.

12.If the reading is less than 40 VDC or not present, perform the DC Buss Power

Supply PC Board Test.

13.Also check leads #303A, #330, #303, #403, #230 and their associated plugs for loose or faulty connections. See the Wiring Diagram.

TEST FOR CONTACT CONTINUITY

1.Disconnect input power to the Multi-Weld 350.

WARNING

ELECTRIC SHOCK can kill.

Disconnect input power before removing the case cover and performing tests or making repairs to the machine.

2.Perform the Power Module Capacitor Discharge procedure.

3.Locate the input contactor and coil leads #303A and #330. See Figure F.3.

4.Label and disconnect leads #303A and #330 at their in-line connectors.

5.Using the external, isolated 40 VDC power supply, carefully apply 40 VDC to the coil leads. The contactor should activate.

6.With the contactor activated, check the con- tinuity across the large contacts. (Zero ohms or very low resistance is normal.) See Figure F.3. If the resistance is high, the input contactor is faulty. Replace the input contactor.

7.When the contactor is not activated, the resistance should be infinite or very high across the contacts. If the resistance is low, the input contactor is faulty. Replace the input contactor.

8.Remove the 40 VDC external supply and reconnect the coil leads previously removed.

9.If finished testing, perform the Case Cover Replacement procedure.

MULTI-WELD 350

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Contents Multi-Weld TM 350 Arc Converter California Proposition 65 Warnings SafetyElectric Shock can kill Iii Welding Sparks can cause fire or explosionSûreté Pour Soudage a L’Arc Précautions DE SûretéMaster Table of Contents for ALL Sections Table of Contents Installation Section Technical Specifications MULTI-WELD 350 K1735-1 InstallationQUICK-CONNECT PIG-TAILS Safety PrecautionsCase Grounding Work ConnectionFixed Parallel Operation Converters Cable Size On Cable AWG mm2 Power Source SetupTable of Contents Operation Section Operating Instructions Safety InstructionsOperation Portable Product DescriptionVersatile Distribution BOX MULTI-SYSTEM Power SourcePIG-TAIL Leads and Connectors Recommended Equipment and ProcessesRemote Output Control Options CV Mode Wire WeldingCC Mode Stick Welding and Gouging Front Panel Controls Input Power/ Mode Switch has three positionsRecessed Panel Controls Cable Handling For CC STICK/GOUGE Mode onlyParalleled Converters Transporting and Storage of the MULTI-WELDProtection Features MULTI-WELD Table of Contents Accessories Section Connection of Lincoln Electric Wire Feeders AccessoriesOPTIONS/ACCESSORIES Semiautomatic Welding AccessoriesTo Work MULTI-WELD Section D-1 Table of ContentsMaintenance Section See additional warning information throughout this manual MaintenanceMaintenance Figure D.2 Major Component Locations ServiceMULTI-WELD Table of Contents Theory of Operation Section General Description Theory of OperationFigure E.3 Power Modules and Feedback Power Modules and FEED- BackAnalog Control Power Supply Board and Weld Control Board Figure E.5 Mode Selector and Output Controls Mode Selector and Output ControlsOVER-VOLTAGE Protection Insulated Gate Bipolar Transistor Igbt Operation 8E-8 Pulse Width Modulation70-80VDC Chopper Technology FundamentalsMULTI-WELD Table of Contents Troubleshooting & Repair Section HOW to USE Troubleshooting Guide Troubleshooting & RepairPC Board can be damaged by static electricity PC Board Troubleshooting ProceduresBoard Test Troubleshooting GuidePower Supply Board Test Perform the DC Buss SupplyVoltage Test SpecificationsPerform the Input Contactor Coil Resistance and SupplyTest Input Voltage and ResistanceFunction Problems See the Digital Meter Calibra Analog Control Power Supply Board TestTion and Adjustment Test Perform the DC Buss Supply Welding Problems Troubleshooting & Repair Troubleshooting & Repair Materials Needed Case Cover Assembly Removal Replacement ProcedureTest Description Replacement Procedure Removal ProcedurePower Module Capacitor Discharge Procedure Figure F.2 Power Module Capacitor Terminal Discharge ProcedureInput Contactor Coil Resistance and Supply Voltage Test Leads #303A #330 Coil Test ProcedurePerform the Power Module Capacitor Discharge procedure Input Contactor Coil Resistance Supply Voltage TestSupply PC Board Test Test for Contact ContinuityAnalog Control Power Supply PC Board Test Figure F.4 Analog Control Power Supply PC Board Test ProcedurePower Supply PC Board Test DC Buss Power Supply PC Board Test P46 P47 DC Buss Power Supply PC BoardTable F.2 DC Buss Power Supply PC Board Voltage Table Chopper PC Board Input Voltages and Resistance Test Chopper PC Board Input Voltages Resistance Test Figure F.6 Power Module Assembly DetailsPower Module Capacitor Discharge Procedure Test Procedure for the Left Side Power ModuleNormal Open Circuit Voltage Waveform CC Mode Input Voltage Applied 75 VDCScope Settings CV Mode Output Control AT Maximum Normal Weld Voltage Waveform Machine Loaded to 350 Amps AT 34 Volts CC-STICK ModeMachine Loaded to 350 Amps AT 34 Volts CV Mode CV Mode Output Control AT Minimum Description Case Front Assembly Removal and ReplacementReplace the case cover Weld Control or Peripheral PC Board Removal and Replacement Figure F.8 Case Front Assembly Details Replacement Procedure Description Lens Bezel Spacer Seal Knob Digital Meter Removal ProcedureRefer to Figure F.9 Output Control Potentiometer Removal ProcedureInput Contactor Removal and Replacement Lead #331 Figure F.10 Input Contactor Assembly DetailsReplacement Procedure Input Diode Removal and Replacement Figure F.11 Input Diode Assembly Details Refer to Figure F.11 25-27 300-324FAN Motor Assembly Removal and Replacement Figure F.12 FAN Motor Assembly Details Perform the Input Diode Removal proce- dure Perform the Input Diode Replacement procedurePower Capacitor Removal and Replacement Figure F.13 Power Capacitor Mounting Details Reassembly Chopper PC Board and Diode Module Removal and Replacement Removal Chopper PC Board Removal and ReplacementRefer to Figure F.14 ReplacementFigure F.15 Diode Module Mounting Details Diode Module Removal and ReplacementRefer to Figure F.15 Figure F.16 Diode Module Tightening Sequence Load Test Retest After RepairIdle Amps Open Circuit VoltagesTable of Contents Electrical Diagrams Section Electrical DiagramsWiring Diagram MULTI-WELD MULTI-WELD 350 Wiring DiagramSchematic Control PC Board #1 Schematic Control PC Board #2 Schematic Control PC Board #3 Schematic Control PC Board #4 Schematic Control PC Board #5 RESISTOR,SMD,1W,243OHMS,1% PC Board ASSEMBLY-CONTROLSchematic Peripheral Printed Circuit Board PC Board Reference Description Designators PC Board ASSEMBLY-PERIPHERALSchematic Power Printed Circuit Board Return to Section Return to Section TOC To Section TOC PC Board ASSEMBLY-POWERSchematic Analog Printed Circuit Board PC Board ASSEMBLY-ANALOG Schematic BY-PASS Printed Circuit Board PC Board Assembly BY-PASS 19303 M Schematic Chopper Printed Circuit BoardPC Board Assembly Chopper SVM Error Reporting Form