Lincoln Electric SVM123-A service manual Troubleshooting & Repair

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F-44	TROUBLESHOOTING & REPAIR	F-44
	TROUBLESHOOTING & REPAIR

ABNORMAL OPEN CIRCUIT VOLTAGE WAVEFORM

CONSTANT VOLTAGE INNERSHIELD

ONE OUTPUT SCR NOT FUNCTIONING

MAXIMUM OUTPUT SETTING

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This is NOT the typical DC output volt- age waveform. One output SCR is not functioning. Note the “gap” in the wave- form. One SCR gate is disconnected to simulate an open or nonfunctioning out- put SCR. Each vertical division repre- sents 50 volts and each horizontal divi- sion represents 2 milliseconds in time.

Note: Scope probes connected at

machine ouput terminals: (+) probe to positive 1000 amp terminal, (-) probe to negative terminal.

SCOPE SETTINGS

Volts/Div. . . . . . . . . . . . . 50 V/Div. Horizontal Sweep . . . . . 2 ms/Div. Coupling . . . . . . . . . . . . . . . . . DC Trigger . . . . . . . . . . . . . . . Internal

IDEALARC DC-1000

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Contents Idealarc Safety Electric and Magnetic FieldsElectric Shock can kill Welding Sparks can cause fire or explosion Précautions DE Sûreté Sûreté Pour Soudage a L’ArcMaster Table of Contents for ALL Sections Installation Technical Specifications Idealarc DC OutputElectric Shock can Kill Select Proper LocationElectrical Input Connections StackingReconnect Procedure Fuse and Wire SizesInput Power Supply Connections Ground ConnectionFigure A.3a Input Connection Diagram Figure A.3c -Input Connection Diagram Figure A.3d Input Supply Connection Diagram Output Connections Connection for AIR/CARBON ARC Cutting OperationIdealarc DC-1000 Operation Safety Instructions Electric Shock can killOperational Features and Controls Design Features AdvantagesGeneral Description Recommended Processes and EquipmentWelding Capability Controls and Settings Return to SectionWelding Procedure Recommendations Remote Control of Machine OperationNA-3 Automatic Wire Feeder ARC Striking with Idealarc DC-1000 and the NA-3 Start Board LN-8 SEMI-AUTOMATIC Wire Feeder RemoteAccessories Table of ContentsOPTIONS/ACCESSORIES Connecting the NA-3 or LT-7 toIdealarc DC-1000 Remote Output Control OptionalConnecting the NA-5 to the Idealarc DC-1000 Figure C.2 NA-5 Wire Feeder Connection to Idealarc DC-1000Connecting the LN-8 to the Idealarc DC-1000 Connecting the LN-9 Wire Feeder to the Idealarc DC-1000 Connecting the LN-7 Wire Feeder to the Idealarc DC-1000 Maintenance Safety Precautions Electric Shock Can Kill Routine and Periodic MaintenanceFigure D.1 Major Component Locations Idealarc DC-1000 Theory of Operation Input Line VOLTAGE, Contac TOR, and Main TransformerOutput Rectification CONTROL, and FeedbackProtection Devices Circuits Contactor HOLD-INSCR Operation Figure E.5 SCR OperationIdealarc DC-1000 Troubleshooting & Repair HOW to USE Troubleshooting Guide Locate Problem SymptomPC Board Troubleshooting Procedures Board can be damaged by static electricityControl Transformer Test Return Return to Master TOC Return Return to Section TOC Perform SCR Output Bridge Troubleshooting & Repair Function Problems Perform Firing Board Test Perform Control Board Test SCR Output Troubleshooting & Repair Test Description Control Transformer T2 Voltage TestTest Procedure Figure F.1 Control Transformer Lead LocationFigure F.2 Control Transformer X1 and X2 Test Points Main Transformer T1 Voltage Test Test Description Figure F.4 Main Secondary Lead Test Points From Expected VAC Firing Board Test Test Procedure for Normal Firing Board Operation Figure F.7 Terminal Strip Jumper Wire Connections Figure F.8 Output Pilot Relay 4CR Location Table F.1 LED 7, 8 and 9 Check List ThenControl Board Test Test Procedure for Normal Control Board Operation Figure F.9 Control Board LED and Pin LocationsPossible Problems Pertaining to the Control Board If LED 1 does not light, when the start switch is onFigure F.11 LED 2 Open Circuit Voltage Test Points If LED 4 lights Static SCR Test Test Procedure Figure F.12Figure F.13 SCR Heat Sink Assembly Test Points Static SCR Test Active SCR Test Active SCR Test Figure F.16 Heat Sink Assembly Test Points Battery Test Scope Settings Troubleshooting & Repair Troubleshooting & Repair Troubleshooting & Repair Troubleshooting & Repair Troubleshooting & Repair Troubleshooting & Repair Input Contactor 1CR Cleaning AND/OR Replacement Cleaning Procedure Figure F.18 Input Contactor Cover RemovalContactor Replacement RemovalInstallation SCR Output Bridge Replacement SCR Output Bridge Removal Figure F.22 Preparation For SCR Output Bridge RemovalFigure F.23 SCR Output Bridge Removal Removal of Individual SCR Heat Sink Assemblies SCR Heat Sink Installation SCR Output Bridge InstallationTOC Removal and Reassembly of Lift Bail Removal of Lift Bail Figure F.25 Lift Bail RemovalReassembly of Lift Bail Main Transformer Removal and Installation Main Transformer Disassembly and Assembly Figure F.26 Main Transformer DisassemblyMain Transformer Disassembly Coil Removal ReplacementTransformer Installation Transformer ReassemblyIdealarc DC-1000 Input Idle Amps and Watts Open Circuit VoltagesIdealarc DC-1000 Electrical Diagrams Idealarc DC-1000 Wiring Diagram Codes 9919 Operating Schematic Control PC Board G1585 Layout Firing PC Board G1486-5 and above Layout Control PC Board G1585 Schematic Firing PC Board G1486-5 and above Schematic Output Snubber M14312 Schematic