Lincoln Electric V250-S service manual Perform the Output Diode Test

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	F-8	TROUBLESHOOTING & REPAIR			F-8
	Observe all Safety Guidelines detailed throughout this manual

	PROBLEMS		POSSIBLE AREAS OF	RECOMMENDED
	(SYMPTOMS)		MISADJUSTMENT(S)	COURSE OF ACTION

OUTPUT PROBLEMS

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The machine will not produce more than 200 amps.

1.This may be normal operation. If the output current exceeds 290 amps, an electronic protection circuit will reduce the current to less than 200 amps. The machine will continue to produce this low current until the protection circuit is reset. Reset occurs when the output load is removed.

2.Check the input voltage and input voltage reconnect procedures. See Input Voltage Reconnect Procedure.

3.Check for loose or faulty welding cables.

1.Perform the Output Diode Test .

2.The control board may be faulty. Replace.

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CAUTION

If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353.

INVERTEC V250-S

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Contents Invertec V250-S Safety ARC Rays can burn Electric Shock can killFumes and Gases can be dangerous Cylinder may explode if damaged Welding Sparks can cause fire or explosionPrécautions DE Sûreté Sûreté Pour Soudage a L’ArcMaster Table of Contents for ALL Sections Installation Table of Contents Installation SectionThree Phase Single Phase Technical Specifications Invertec V250-SThree Phase Input Connections Safety PrecautionsSelect Suitable Location Input Fuse and Supply Wire Input Voltage Reconnect ProcedurePower Input Connection for 50/60 HZ Machines Remote Control Receptacle Output ConnectionsQuick Disconnect Plugs Output CablesInvertec V250-S Operation Safety Instructions Gouging SparksControls and Settings Figure B.1 Case Front ControlsConstant Current Processes Manual ARC Welding StickAIR Carbon ARC Cutting TIG WeldingOverload Protection Parallel OperationThermal Protection Invertec V250-S Accessories Table of Contents Accessories SectionRemote Controls Options / AccessoriesCable Plugs Maintenance Table of Contents Maintenance SectionInput Filter Capacitor Discharge Procedure Figure D.1 Location of Input Filter Capacitor TerminalsRoutine Maintenance Filter Capacitor ConditioningFigure D.2 Location of Maintenance Components Table of Contents Theory of Operation Section Theory of OperationGeneral Description Input Line VoltagePrecharge and Protection Figure E.2 Protection and PRE-CHARGE CircuitsMain Transformer Figure E.3 Main TransformerOutput Rectification Control Figure E.4 Output Rectification and ControlProtection Circuits Overload ProtectionInsulated Gate Bipolar Transistor Igbt Operation Minimum Output Pulse Width ModulationMaximum Output Troubleshooting & Repair HOW to USE Troubleshooting Guide Oscilloscope WarningPC Board Troubleshooting Procedures Board can be dam- aged by static electricityPossible Areas Recommended Symptoms Course of ActionPossible Areas Perform the Control Board Voltage ChecksCapacitor Balance Test Troubleshooting & Repair Perform the Output Diode Test Welding Problems Invertec V250-S Test Description Auxiliary Transformer TestMaterials Needed Test Procedure Auxiliary Transformer TestAuxiliary Transformer Test Table F.1 Auxiliary Transformer Test PointsInvertec V250-S Input Rectifier Test Test Procedure Input Rectifier TestTable F.2 Input Rectifier Test Points Test Point Terminals Analog Meter X10 RangeInvertec V250-S Power Board Resistance Test Power Board Resistance Test Test DescriptionPower Board Resistance Test Table F.3 Power Board Resistance Test PointsInvertec V250-S Output Diodes Test Output Diodes Test Figure F.4 Machine Output TerminalsInvertec V250-S Diode Modules Power Board Voltage Test Power Board Voltage Test Figure F.8 Plug J6 on Power BoardAcceptable Test Description Table F.4. Power Board Voltage Test PointsTest Conditions Invertec V250-S Control Board Voltage Test Control Board Voltage Test Figure F.9 Plugs J1-J5 on Control BoardTable F.5. Control Board Voltage Test Points 18VACInvertec V250-S Protection Circuit Test Protection Circuit Test Figure F.10 Control Board Plug J2 Test PointsProtection Circuit Simplified Invertec V250-S Capacitor Balance Test Figure F.12 Power Board and Capacitor Test Locations Capacitor Balance TestTable F.6 Capacitor Voltages Invertec V250-S Control Board Removal and Replacement Procedure Control Board Removal and ReplacementV250S Control Power Board Removal and Replacement Power Board Removal and Replacement Figure F.14 Power Board Lead LocationsPower Board Replacement Procedure Invertec V250-S Filter Capacitor Removal and Replacement Matched PartsFilter Capacitor Removal and Replacement Figure F.15 Heatsink/Power Board RemovalPerform Power Board Replacement Procedure in this section Invertec V250-S Input Rectifier Bridge Removal and Replacement Input Rectifier Bridge Removal and Replacement Figure F.16 Input Rectifier Lead LocationsTroubleshooting & Repair Invertec V250-S Materials Needed Snubber Resistors Locking Tabs Invertec V250-S Wrench Allen type wrench Torque wrench Mounting Bolts Diode Modules Bolted Connections Troubleshooting & Repair Invertec V250-S Main Transformer Removal and Replacement Machine Codes below T3 Current Transformer Main Transformer Main Transformer Secondary Leads Figure F.22 Main Transformer Mountings Clear all leads and secure for case wrap-around assembly Invertec V250-S Main Transformer Removal and Replacement Machine Codes Above Figure F.23 Main Transformer Right Side Figure F.24 Main Transformer Left Side Figure F.25 Main Transformer Mountings Troubleshooting & Repair Invertec V250-S Maximum Acceptable Output AT Minimum Output Settings Minimum Acceptable Output AT Maximum Output SettingsRetest After Repair Input Idle Amps and Idle WattsInvertec V250-S Electrical Diagrams Invertec V250-S Wiring Diagram Codes 10102 Invertec V250SWiring Diagram Codes 10187 Return to SectionControl PC Board G2666 Layout G2666Power PC Board G2684 Layout Power P.C. BD. AsblyControl PC Board G2666 Schematic Relay CoilsPower PC Board G2684 Schematic From Control BD