Lincoln Electric SVM169-A service manual Active SCR Test

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F-25

TROUBLESHOOTING & REPAIR

F-25

ACTIVE SCR TEST

WARNING

Service and repair should be performed by only Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and pre- cautions detailed throughout this manual.

If for any reason you do not understand the test procedures or are unable to per- form the test / repairs safely, contact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call 1-888-935-3877.

TEST DESCRIPTION

This procedure will determine if the device is able to be gated “ON” and conduct current from anode to cathode.

MATERIALS NEEDED

An SCR tester as outlined in this procedure.

Precision TIG 185 Wiring Diagrams

3/8” nutdriver

PRECISION TIG 185

Image 63

Contents Precision TIG Safety Electric Shock can kill Welding Sparks can cause fire or explosion SafetySûreté Pour Soudage a L’Arc Précautions DE SûretéMaster Table of Contents for ALL Sections Installation Section Table of ContentsInput Single Phase only InstallationK2345-2 Input at Rated Output Model Height Width Depth WeightSelect Suitable Location Safety PrecautionsInput Connections TIG Torch Connection Input Reconnect ProcedureOutput Connections Connections for TIG Gtaw WeldingRemote Control Connection Work Cable ConnectionShielding GAS Connection Precision TIG Section B Operation SectionOperation Recommended Processes and Equipment Product DescriptionControl Functionality Controls and SettingsWelding in TIG Mode Operating StepsPulse TIG Control Benefits of the Precision TIG 185 Design Remote Control OperationRecommended Electrode Amperage Ranges Precision TIG Welding in Stick ModePrecision TIG Accessories Section Accessories Factory Installed OptionsTable C.1 K2348-1 Under-Storage Cart Field Installed OptionsPrecision TIG Section D Maintenance SectionMaintenance Routine and Periodic MaintenanceSpark GAP Adjustment Figure D.2 Location of Maintenance Components Return to Section TOC Section E Theory of Operation SectionInput Power Circuit Theory of OperationGeneral Description Figure E.3 Control Board and Output Feedback Control Output Rectification Feedback ControlFigure E.4 High Voltage/High Frequency Circuit High Voltage / High Frequency CircuitFigure E.5 DC Welding Current Generation DC Welding OutputFigure E.6 AC Square Wave Welding Current Generation AC Welding OutputFigure E.7 SCR Operation SCR OperationProtective Circuits Thermal ProtectionOverload Protection Section F Troubleshooting & Repair SectionHigh Voltage / High Frequency can damage test equipment Troubleshooting & RepairWorkstations PC Board Troubleshooting ProceduresCourse of Action Problems Possible Areas Recommended SymptomsPossible Areas Recommended Symptoms Problems Possible Areas Check the welding cables and or TIG Mode Problems Troubleshooting & Repair TIG Welding Problems Problems Possible Areas Electric Shock can Problems Possible Areas Recommended Symptoms Stick Welding Problems Test Description High Frequency Circuit Disable ProcedureFigure F.1 Spark GAP Assembly ProcedureT1 Transformer Test T1 Transformer Test Test ProcedurePrimary Windings Primary Voltages Return to Section Section TOCPrecision TIG Static SCR Test Static SCR Test Assembly Removal and Replacement Precision TIG Active SCR Test Active SCR Test Figure F.6 SCR Gate Locations Precision TIG AC TIG Mode Scope SettingsNormal Open Circuit Voltage Waveform DC TIG Mode AC Stick Mode DC Stick Mode Machine Loaded to 180 Amps AT 16VDC Typical Output Voltage Waveform Machine LoadedDC TIG Mode Machine Loaded to 180 Amps AT 26VDC DC Stick Mode 50 V/Div Precision TIG SCR Bridge Assembly Removal and Replacement Procedure Troubleshooting and RepairProcedure SCR Bridge AssemblyFront Panel Mounting Screws Figure F.9 Plug J2 on Control Board 42TROUBLESHOOTING & REPAIRF-42Replacement Procedure 43TROUBLESHOOTING & REPAIRF-43Precision TIG Polarity Switch Removal and Replacement Procedure Removal Procedure Polarity SwitchReplacement Procedure Precision TIG High Voltage Transformer Removal and Replacement Procedure Transformer Secondary Leads Precision TIG High Voltage TransformerFigure F.12 High Voltage Transformer Mounting Insulators Precision TIG Nutdriver Wrench Wire cutters Perform the SCR Bridge Assembly Removal Procedure Assembly Replacement Procedure Precision TIG Recommended Meters for Machine Output Tests Troubleshooting and RepairRetest After Repair Input Idle AmpsPrecision TIG Electrical Diagrams Section Precision TIG Wiring Diagram Entire Machine G4549G4588 Schematic Entire Machine G4588Schematic Control PC Board G4550-1B4-1 Schematic Control P.C. Board G4550-1B4-2 Schematic Control P.C. Board G4550-1B4-3 G4551 PC Board Assembly Control G4551-1SVM Error Reporting Form