Lincoln Electric V250-S service manual Welding Problems

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F-9	TROUBLESHOOTING & REPAIR					F-9
	Observe all Safety Guidelines detailed throughout this manual

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

			WELDING PROBLEMS

Poor welding, weld settings drift, or 1.			Make sure the machine settings	1.	Check the operation of the mode
output power is low.			are correct for the weld process		switch (S2) and the associated
			being used.		circuitry. See wiring diagram.
	2.		Check machine performance on	2.	Check for loose or faulty connec-
			LOCAL control. If OK then the		tions in the heavy current carrying
			remote control device may be		leads (i,e,. output diodes, output
			faulty. Check or replace.		terminals, shunt and main trans-
					former.)
		3. Check the input voltages and
			input voltage reconnect	3.	Perform Output Diode Test.
			procedures. See Installation
			Section of this manual.	4.	Perform Control Board Voltage
					Test .

Poor stick electrode welding	1.	Check for loose or faulty welding
performance. The arc pops out.		cables.	1.	Check for loose or faulty connec-
				tions in the heavy current carrying
	2.	Is the electrode DRY? Try weld-		leads (i,e,. output diodes, output
		ing with another electrode from a		terminals, shunt and main trans-
		different container. Make sure		former.)
		you have the correct electrode for
		the application.	2.	Perform Output Diode Test.
	3.	Make sure the machine settings	3.	Perform Control Board Voltage
		are correct for the weld process		Test.
		being used.

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 Fumes and Gases can be dangerous Electric Shock can killARC Rays can burn Welding Sparks can cause fire or explosion Cylinder may explode if damagedSûreté Pour Soudage a L’Arc Précautions DE SûretéMaster Table of Contents for ALL Sections Table of Contents Installation Section InstallationThree Phase Technical Specifications Invertec V250-SThree Phase Single Phase Select Suitable Location Safety PrecautionsInput Connections Power Input Connection for 50/60 HZ Machines Input Voltage Reconnect ProcedureInput Fuse and Supply Wire Output Connections Remote Control ReceptacleQuick Disconnect Plugs Output CablesInvertec V250-S Operation Gouging Sparks Safety InstructionsFigure B.1 Case Front Controls Controls and SettingsManual ARC Welding Stick Constant Current ProcessesAIR Carbon ARC Cutting TIG WeldingThermal Protection Parallel OperationOverload Protection Invertec V250-S Table of Contents Accessories Section AccessoriesCable Plugs Options / AccessoriesRemote Controls Table of Contents Maintenance Section MaintenanceFigure D.1 Location of Input Filter Capacitor Terminals Input Filter Capacitor Discharge ProcedureFilter Capacitor Conditioning Routine MaintenanceFigure D.2 Location of Maintenance Components Theory of Operation Table of Contents Theory of Operation SectionInput Line Voltage General DescriptionFigure E.2 Protection and PRE-CHARGE Circuits Precharge and ProtectionFigure E.3 Main Transformer Main TransformerFigure E.4 Output Rectification and Control Output Rectification ControlOverload Protection Protection CircuitsInsulated Gate Bipolar Transistor Igbt Operation Maximum Output Pulse Width ModulationMinimum Output Troubleshooting & Repair Oscilloscope Warning HOW to USE Troubleshooting GuideBoard can be dam- aged by static electricity PC Board Troubleshooting ProceduresCourse of Action Possible Areas Recommended SymptomsPerform the Control Board Voltage Checks Possible AreasCapacitor Balance Test Troubleshooting & Repair Perform the Output Diode Test Welding Problems Invertec V250-S Materials Needed Auxiliary Transformer TestTest Description Auxiliary Transformer Test Test ProcedureTable F.1 Auxiliary Transformer Test Points Auxiliary Transformer TestInvertec V250-S Input Rectifier Test Input Rectifier Test Test ProcedureTest Point Terminals Analog Meter X10 Range Table F.2 Input Rectifier Test PointsInvertec V250-S Power Board Resistance Test Test Description Power Board Resistance TestTable F.3 Power Board Resistance Test Points Power Board Resistance TestInvertec V250-S Output Diodes Test Figure F.4 Machine Output Terminals Output Diodes TestInvertec V250-S Diode Modules Power Board Voltage Test Figure F.8 Plug J6 on Power Board Power Board Voltage TestTest Conditions Table F.4. Power Board Voltage Test PointsAcceptable Test Description Invertec V250-S Control Board Voltage Test Figure F.9 Plugs J1-J5 on Control Board Control Board Voltage Test18VAC Table F.5. Control Board Voltage Test PointsInvertec V250-S Protection Circuit Test Figure F.10 Control Board Plug J2 Test Points Protection Circuit TestProtection Circuit Simplified Invertec V250-S Capacitor Balance Test Capacitor Balance Test Figure F.12 Power Board and Capacitor Test LocationsTable F.6 Capacitor Voltages Invertec V250-S Control Board Removal and Replacement V250S Control Control Board Removal and ReplacementProcedure Power Board Removal and Replacement Figure F.14 Power Board Lead Locations Power Board Removal and ReplacementPower Board Replacement Procedure Invertec V250-S Matched Parts Filter Capacitor Removal and ReplacementFigure F.15 Heatsink/Power Board Removal Filter Capacitor Removal and ReplacementPerform Power Board Replacement Procedure in this section Invertec V250-S Input Rectifier Bridge Removal and Replacement Figure F.16 Input Rectifier Lead Locations Input Rectifier Bridge Removal and ReplacementTroubleshooting & 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 Minimum Acceptable Output AT Maximum Output Settings Maximum Acceptable Output AT Minimum Output SettingsRetest After Repair Input Idle Amps and Idle WattsInvertec V250-S Electrical Diagrams Invertec V250-S Invertec V250S Wiring Diagram Codes 10102Return to Section Wiring Diagram Codes 10187G2666 Control PC Board G2666 LayoutPower P.C. BD. Asbly Power PC Board G2684 LayoutRelay Coils Control PC Board G2666 SchematicFrom Control BD Power PC Board G2684 Schematic