Lincoln Electric SVM 122-A service manual 2V/Div

Page 82

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F-38

F-38

TROUBLESHOOTING & REPAIR

TYPICAL SCR GATE VOLTAGE WAVEFORM

CONSTANT VOLTAGE SUBARC

MAXIMUM OUTPUT SETTING – NO LOAD

CH1

0 volts

2 volts

5 ms

This is the typical SCR gate pulse voltage waveform. The machine was in an open circuit condition (no load) and operating properly. Note that each vertical division represents 2 volts and that each horizontal division represents 5 milliseconds in time.

Note: Scope probes connected at

SCR gate and cathode: (+) probe to gate, (-) probe to cathode.

SCOPE SETTINGS

Volts/Div	2V/Div.
Horizontal Sweep	5 ms/Div.
Coupling	DC
Trigger	Internal

IDEALARC DC-400

LINCOLN ®

ELECTRIC

Image 82

Contents Safety Depends on You Idealarc TMDC-400Safety California Proposition 65 WarningsElectric Shock can kill Cylinder may explode if damaged Précautions DE Sûreté Master Table of Contents for ALL Sections Table of Contents Installation Section Installation Technical Specifications Idealarc DC-400Lifting Safety PrecautionsSelect Suitable Location TiltingInput Supply Connections Input ConnectionsGround Connection Electric Shock can killInput Wire and Fuse Size Figure A.3 Input Power Supply ConnectionsReconnect Procedure Input Supply Connection DiagramOutput Connections Figure A.6 Output Terminal ConnectionsCycle 500 Amp 50% Duty Wire Feeder ConnectionsCycle Operation Section OPERATIONB-2 Safety InstructionsOperating Instructions Operation General DescriptionControls and Settings Figure B.1 Case Front ControlsOperation Welding Operation Remote ControlWelding Procedure Recommendations Operating StepsNA-3 Automatic Wire Feeder ARC Striking with the NA-3 Start BoardNA-5 Automative Wire Feeder LN-8 Semiautomatic Wire FeederAuxiliary Power Overload ProtectionTable of Contents Accessories Field Installed Options OPTIONS/ACCESSORIESFactory Installed Option Diode OptionMultiprocess Switch Operation ConnectionsRemote Output Control K857 with K864 Adapter Plug or K775 Remote Control Adapter Cable K864K843 Amptrol Adapter Installation Instructions Amptrol Adapter Cable K843K843 Amptrol Adapter Installation Instructions Amptrol and Hi-Freq. Kit The Amptrol will startCapacitor Discharge Circuit K828-1 Automatic Wire FeedersConnecting the NA-3 to the Idealarc DC-400 Terminal Strip HI-FREQ KIT K799 for Codes 8634 and Above onlyConnecting the NA-5 to the Idealarc DC-400 Terminal Strip Cable Plug K597-XX Input Cable Assembly Idealarc DC-400 To NA-3 or NA-5 InputSemiautomatic Wire Feeders Connecting the LN-7 to the Idealarc DC-400 14-PIN AmphenolConnecting the LN-7 to the Idealarc DC-400 Terminal Strip Accessories Accessories Figure C.11 Idealarc DC-400/LN-742 Connection Diagram Table of Contents Maintenance Routine and Periodic Maintenance Figure D.1 General Component Locations Table of Contents Theory of Operation Section Contactor and Main Theory of OperationInput Line Voltage TransformerOutput Mode and CONTROL, Rectification and Feedback Protective Devices and Circuits SCR Operation Figure E.4 SCR OperationTable of Contents Troubleshooting & Repair Section Troubleshooting & Repair HOW to USE Troubleshooting GuidePC Board Troubleshooting Procedures PC Board can be damaged by static electricityTroubleshooting Guide Output ProblemsPerform the Main Transformer Rectifier Bridge Test Tifier Bridge Test Output Problems Test Perform the SCR/Diode Rec Tifier Bridge Test Function Problems Form the SCR/Diode Rectifier Welding Problems Trolyte in these capacitors is Portion of your body. CleanToxic. Avoid contact with any Make sure welding process is Description Input Contactor TestMaterials Needed Test Procedure Input Contactor TestTest for Contact Continuity Figure F.2 Input Contactor Test ConnectionsControl Transformer T2 Voltage Test Control Transformer T2 Voltage Test Figure F.3 Control Transformer and Lead LocationsTroubleshooting & Repair Main Transformer T1 Voltage Test Main Transformer T1 Voltage Test Figure F.6 Main Secondary Lead Test Points Troubleshooting & Repair Plug P1 Phase Angle Winding Voltages Figure F.8 Control Board Plug P1 LocationStatic SCR/DIODE Rectifier Bridge Test Static SCR/DIODE Rectifier Bridge Test Figure F.9 Control Board and Snubber Board Plug LocationsSCR Test Active SCR Test Active SCR Test P1 and P3 Locations Plug P5 LocationFigure F.15 Heat Sink Test Points Figure F.16 SCR Tester Circuit and SCR Connections Scope Settings CH1Maximum Output Setting no Load Troubleshooting & Repair Troubleshooting & Repair Troubleshooting & Repair 2V/Div Troubleshooting & Repair Input Contactor CR1 CLEANING/REPLACEMENT Cleaning Procedure Input Contactor CR1 CLEANING/REPLACEMENTContactor Replacement Procedure FAN Motor and Blade Removal and Replacement FAN Motor and Blade Removal and Replacement ProcedureSCR/DIODE Rectifier Assembly Removal and Replacement SCR/DIODE Rectificer Assembly Removal and ReplacementSCR Removal and Replacement SCR Removal and Replacement Special InstructionsProcedure for the 1/2 Inch Wide Spring Figure F.21 1/2 Wide Leaf SpringClamping Procedure For 1/4-28 CAP Screws Clamping Procedure For 1/4-20 CAP ScrewsProcedure for Inch Wide SpringAfter Replacing the SCRs Mounting of Stud Type Diodes to Aluminum Heat Sinks Heat Sinks Mounting of Stud Type Diodes to AluminumDiode Stud Foot Inch Size Pounds Main Transformer Removal and Replacement Main Transformer Removal & Replacement Removal of Lift BailRemoval of Choke and TOP Iron Assembly Figure F.26 Choke RemovalReassembly of Transformer Coils Figure F.27 Epoxy MIX Application AreasFigure F.28 Coil Lead Placement Figure F.30 Primary Thermostat Location Reassembling the Main Transformer Into the Machine Reassemble the Lift BailRetest After Repair Input volts/Phase/Hertz Maximum Idle Amps Maximum Idle KWMode Input Hertz Open Circuit Volts Input Idle Amps and WattsMode Control Settings Load Maximum Acceptable Output Voltage AT Minimum Ouput SettingsRetest After Repair Table of Contents Electrical Diagrams Section Idealarc DC400 Wiring Diagram Codes 9847 LOW VoltageWiring Diagram Code Only. It may not be accurate for allControl PC Board G2588 Layout Control DC400Starting PC Board M14520 Layout TP2Snubber PC Board M15370 Layout Control PC Board G2588 Schematic 2586Starting PC Board M14520 Schematic General InformationSnubber PC Board M15370 Schematic General Information