Lincoln Electric SVM 113-A service manual Output Rectifier Bridge Test

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F-19

F-19

TROUBLESHOOTING & REPAIR

OUTPUT RECTIFIER BRIDGE TEST (continued)

FIGURE F.4 - OUTPUT RECTIFIER BRIDGE

203

Strap

W2

W1

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TEST PROCEDURE

1.Conduct this test with the gasoline engine OFF.

2.Remove the spark plug wire to prevent accidental engine kickback or starting.

3.With the 5/16" nut driver, remove the 8 sheet metal screws that hold the top cover to the control box. Remove the top cover.

4.Locate the output rectifier bridge.

5.With the 7/16" wrench, remove the nuts and washers that hold the four diode pigtail leads and the heavy current carrying leads to the studs located at the front of the rec- tifier bridge assembly. Note lead place- ment for reassembly. See Figure F.4.

6.Electrically isolate the diode pigtails.

7.With the volt/ohmmeter or diode tester, check the resistance of each of the four diodes from their pigtail leads to their respective heat sinks. Alternate placement of the test probes. Resistance should be high in one direction and low in the other.

8.Replace any shorted or open diodes.

9.Reassemble the heavy current carrying leads and pigtails to their respective studs. The proper fastener sequence is: pigtail - lead - flat washer - lock washer - nut.

10.Replace the top cover on the control box. Tighten the 8 sheet metal screws with the 5/16" nut driver.

WELDANPOWER 125

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Contents Weldanpowertm California Proposition 65 Warnings SafetyElectric Shock can kill Cylinder may explode if damaged Précautions DE Sûreté Master Table of Contents for ALL Sections Table of Contents Installation Section Technical Specifications Weldanpower InstallationSafety Precautions Location and VentilationStoring PRE-OPERATION Engine Service Welding Cable Connections Electrical Output ConnectionsAuxiliary Power Receptacles Machine GroundingPlugs and HAND-HELD Equipment Circuit Breakers Premises WiringThese Devices Without Table of Contents Operation Section Operation Safety InstructionsOperating Instructions General DescriptionDesign Features Advantages Operational Features and ControlsRecommended Applications Welding CapabilityWELDER/GENERATOR Controls Controls and SettingsFigure B.2 Gasoline Engine Controls Gasoline Engine ControlsEngine Operation Before Starting the EngineStarting the Engine For Best Engine Starting Stopping the EngineBREAK-IN Period Welding OperationGeneral Information LOW OIL SensingTIG Welding To USE the Weldanpower 125 for WELD- INGTable B.2 Electrode Selection Guide To USE the Weldanpower 125 AS AN Auxiliary Power Supply Auxiliary PowerTable B.3 Generator Power Applications Table of Contents Accessories OPTIONS/ACCESSORIES Lincoln Electric AccessoriesBriggs and Stratton Accessories Table of Contents Maintenance Engine Maintenance Routine and Periodic MaintenanceMaintanence Figure D.3 Clean Finger GuardFigure D.5 SET Spark Plug GAP Table D.2 Engine Maintenance Parts WELDER/GENERATOR MaintenanceFigure D.6 Major Component Locations Table of Contents Theory of Operation Section Idler Board ENGINE, EXCITATION, Rotor and StatorAuxiliary Power Overcurrent Protection Rotor Field Feedback Auxiliary Power Engine Idle ControlFigure E.4 Weld WINDING, Output Rectifier and Choke Weld WINDING, Output Rectifier and ChokeTable of Contents Trouble Shooting & Repair Section HOW to USE Troubleshooting Guide Troubleshooting & RepairElectric Shock can kill PC Board Troubleshooting ProceduresOutput Problems Troubleshooting GuideOutput Rectifier Troubleshooting & Repair Perform the Engine Throttle Engine Problems Main Stator Winding Test Engine Throttle Adjustment Troubleshooting & Repair Weldanpower Rotor Voltage Test Test DescriptionMaterials Needed Rotor Voltage Test Test ProcedureRotor Resistance Test Rotor Resistance Test Figure F.3 Brushes Retained with Cable TIE Output Rectifier Bridge Test Output Rectifier Bridge Test Main Stator Test Main Stator Test Figure F.6 Main Stator Molex Plug Test Points Rotor Flashing Circuit Test Rotor Flashing Circuit Test WP125 Idler Engine Throttle Adjustment Test Test Procedure Figure F.12 Idle Speed Adjustment Screw Locations Figure F.13 LOW Idle Adjustment NUT on Idler Solenoid TOC Scope Settings Normal Open Circuit Weld Voltage WaveformHigh Idle no Load Output Control AT Maximum Normal Open Circuit Voltage Waveform 115 VAC Supply Typical Weld Output Waveform Machine LoadedMachine Loaded to 125 Amps AT 25 VAC Abnormal Open Circuit Weld Voltage Waveform Description Brush Removal and ReplacementFigure F.14 Brushes Retained with Cable TIE ProcedureProcedure Rheostat Removal and Replacement Rheostat Removal and Replacement Field Capacitor Removal and Replacement Field Capacitor Removal and Replacement Field Diode Bridge Removal and Replacement Field Diode Bridge Removal and Replacement Figure F.18 Field Diode Bridge Location Idler Printed Circuit Board Removal Replacement Carefully remove the board Output Rectifier Bridge Removal Replacement Output Rectifier Bridge Removal and Replacement Troubleshooting & Repair Output Choke Removal and Replacement Output Choke Removal and Replacement Section TOC Instructions STATOR/ROTOR Removal and ReplacementStator Removal Procedure Troubleshooting & Repair Reassembly Procedure Rotor Removal ProcedureFigure F.24 Checking ROTOR-STATOR AIR GAP Feeler Gauge Troubleshooting & Repair Retest After Repair Auxiliary Power Receptacle OUTPUT1Engine Output WELDER/GENERATOR OUTPUT1Weldanpower Table of Contents Diagrams Section Wiring Diagram Code 10158 Diagrams SchematicIdler PC Board M17578 Dimension Print Weldanpower Weldanpower M17578-1 M17578 Idler PC BoardDescription M17578 Idler PC Board Bill of MaterialsWeldanpower