Lincoln Electric SVM169-A service manual Perform the SCR Bridge Assembly Removal Procedure

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Section TOC

Master TOC

F-54

TROUBLESHOOTING & REPAIR

F-54

MAIN TRANSFORMER AND OUTPUT CHOKE ASSEMBLY REMOVAL AND REPLACEMENT PROCEDURE (Continued)

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REMOVAL PROCEDURE

1.Remove input power to the TIG 185 machine.

2.Perform the SCR Bridge Assembly Removal Procedure .

3.Unsolder the two 115VAC leads and leads B231 and B232 from the main transformer leads. Label leads for reassembly. See wiring diagram.

4.Unsolder leads W201 and W204 from the main transformer leads. Label leads for reassembly. See wiring diagram.

5.Unsolder leads R209 and U210 from the main transformer leads. Label leads for reassembly. See wiring dia- gram.

6.Using the 1/2” wrench remove the shunt assembly from the choke lead.

7.With the 3/8” wrench remove the H1, H2 or H3 lead from the input power switch. See wiring diagram. Label the leads and connection points for reassembly. Cut any necessary cable ties.

8.Remove plug J3 from the control board and push through the interior divider panel.

9.Using the 1/2” wrench remove the choke lead from the polarity switch. See wiring diagram. Label lead and connection point for reassembly.

10.With the 1/2” wrench remove the X1 secondary lead from the polarity switch. See wiring diagram. Label lead and connection point for reassembly.

11.With the 1/2” wrench remove the four nuts and lock washers from the transformer mounting bolts at the base of the machine.

12.Carefully hoist the transformer/ choke assembly clear of the base. Clear all leads.

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PRECISION TIG 185

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Contents Precision TIG Safety Electric Shock can kill Safety Welding Sparks can cause fire or explosionPrécautions DE Sûreté Sûreté Pour Soudage a L’ArcMaster Table of Contents for ALL Sections Table of Contents Installation SectionInstallation Input Single Phase onlyModel Height Width Depth Weight K2345-2 Input at Rated OutputSafety Precautions Select Suitable LocationInput Connections Input Reconnect Procedure Output ConnectionsConnections for TIG Gtaw Welding TIG Torch ConnectionShielding GAS Connection Remote Control ConnectionWork Cable Connection Precision TIG Operation Section Section BOperation Product Description Recommended Processes and EquipmentControls and Settings Control FunctionalityPulse TIG Control Welding in TIG ModeOperating Steps Remote Control Operation Benefits of the Precision TIG 185 DesignWelding in Stick Mode Recommended Electrode Amperage Ranges Precision TIGPrecision TIG Accessories Section Table C.1 AccessoriesFactory Installed Options Field Installed Options K2348-1 Under-Storage CartPrecision TIG Maintenance Section Section DSpark GAP Adjustment MaintenanceRoutine and Periodic Maintenance Figure D.2 Location of Maintenance Components Return to Section TOC Theory of Operation Section Section EGeneral Description Input Power CircuitTheory of Operation Output Rectification Feedback Control Figure E.3 Control Board and Output Feedback ControlHigh Voltage / High Frequency Circuit Figure E.4 High Voltage/High Frequency CircuitDC Welding Output Figure E.5 DC Welding Current GenerationAC Welding Output Figure E.6 AC Square Wave Welding Current GenerationSCR Operation Figure E.7 SCR OperationOverload Protection Protective CircuitsThermal Protection Troubleshooting & Repair Section Section FTroubleshooting & Repair High Voltage / High Frequency can damage test equipmentPC Board Troubleshooting Procedures WorkstationsProblems Possible Areas Recommended Symptoms Course of ActionPossible 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 High Frequency Circuit Disable Procedure Test DescriptionProcedure Figure F.1 Spark GAP AssemblyT1 Transformer Test Test Procedure T1 Transformer TestReturn to Section Section TOC Primary Windings Primary VoltagesPrecision 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 Normal Open Circuit Voltage Waveform AC TIG ModeScope Settings DC TIG Mode AC Stick Mode DC Stick Mode Typical Output Voltage Waveform Machine Loaded Machine Loaded to 180 Amps AT 16VDCDC TIG Mode Machine Loaded to 180 Amps AT 26VDC DC Stick Mode 50 V/Div Precision TIG Troubleshooting and Repair SCR Bridge Assembly Removal and Replacement ProcedureSCR Bridge Assembly ProcedureFront Panel Mounting Screws 42TROUBLESHOOTING & REPAIRF-42 Figure F.9 Plug J2 on Control Board43TROUBLESHOOTING & REPAIRF-43 Replacement ProcedurePrecision TIG Polarity Switch Removal and Replacement Procedure Polarity Switch Removal ProcedureReplacement Procedure Precision TIG High Voltage Transformer Removal and Replacement Procedure High Voltage Transformer Transformer Secondary Leads Precision TIGFigure 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 Troubleshooting and Repair Retest After RepairInput Idle Amps Recommended Meters for Machine Output TestsPrecision TIG Electrical Diagrams Section Wiring Diagram Entire Machine G4549 Precision TIGSchematic Entire Machine G4588 G4588Schematic Control PC Board G4550-1B4-1 Schematic Control P.C. Board G4550-1B4-2 Schematic Control P.C. Board G4550-1B4-3 PC Board Assembly Control G4551-1 G4551SVM Error Reporting Form