Lincoln Electric SVM144-B service manual Rectifier Diode Bridge Testing

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F-16

TROUBLESHOOTING & REPAIR

F-16

RECTIFIER DIODE BRIDGE TESTING (continued)

FIGURE F.2 — G3521 RECTIFIER DIODE BRIDGE LOCATION.

RECTIFIER

DIODE BRIDGE

(D2)

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TEST PROCEDURE

1.Disconnect the main AC input power to the machine.

2.Remove the case top and side panels with a 3/8 in. nutdriver.

3.Perform the Main Transformer Test to ensure the proper voltages are supplied to the M19248 snubber PC board.

4.Locate the following leads:

LEAD

208R

209R

354

206

Leads #208R, #209R, and #354 are connected to the rectifier diode bridge (D2). See Figure F.2. Lead #206 is connected at the output shunt. See the wiring diagram.

5.Connect main input power to the machine.

POWER MIG 255

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Contents Power MIG 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 Technical Specifications Power MIGSafety Precautions Uncrating the Power MIGLocation Power MIG Figure A.2 Triple Voltage Machine Input Connections GUN and Cable Installation Shielding GASOperation Section Section BOPERATIONB-2 Fumes and Gases can be dangerousWelding Capability OperationProduct Description LimitationsDescription of Controls Procedure for Changing Drive and Idle Roll Sets Wire Reel Loading READI-REELS, SPOOLS, or CoilsIdle Roll Pressure Setting Feeding Wire ElectrodeSetting RUN-IN Speed on STAN- Dard Power MIG Feeder To Start the WelderAvoiding Wire Feeding Problems Making a WeldFAN Control Input Line Voltage ProtectionAccessories Section Section CK363P READI-REEL Adapter AccessoriesDrive Roll Kits Dual Cylinder Mounting KIT K1702-1Operating Instructions For Timer KIT Making a Weld with the Spool GUN, Spool GUN Installed Spool GUN Adapter KITMaintenance Section Section DMaintenance Routine and Periodic MaintenanceGUN Tubes and Nozzles Figure D.1 Component Locations Contact TIP and GAS Nozzle Installation Liner Removal Replacement5MAINTENANCED-5 To open up the handleTable D.2 Description English Size Metric SizeTheory of Operation Section Section ETheory of Operation Input Line VoltageMain Transformer Output Rectification Feedback ControlConstant Voltage Output Figure E.4 Constant Voltage OutputWire Drive Motor FeedbackWire Feed Overload Protection Thermal and Overload ProtectionOvercurrent Protection SCR Operation Figure E.6 SCR OperationPower MIG Troubleshooting & Repair Section Section FTroubleshooting & Repair HOW to USE Troubleshooting GuidePC Board Troubleshooting Procedures WorkstationsOutput Problems SCR Rectifier Rectifier Function Problems Wire Feeding Problems Welding Problems Welding Problems Main Transformer Test Test DescriptionTest Procedure Main Transformer TestFigure F.1 Troubleshooting and Repair Rectifier Diode Bridge Test Test DescriptionMaterials Needed Rectifier Diode Bridge Testing 208R 206 28 VAC 209R Power MIG Static SCR Rectifier Assembly Test Static SCR Rectifier Assembly Test Active SCR Rectifier Assembly Test Power MIG Active SCR Rectifier Assembly Test Active SCR Rectifier Assembly Test Figure F.7 Location Leads X2 Open switch SW-1 Wire Drive Motor and Tachometer Feedback Test Wire Drive Motor and Tachometer Feedback Test Test for Supply Voltage to Tachometer 515B 206B 15 VDC 5J1 1J1Test for Feedback Voltage to Control Board 555 206B To 3.5 VDC 6J1 1J1Normal Open Circuit Voltage Waveform VoltsMachine Loaded to 250 Amps AT 26 VDC Scope Settings Typical Output Voltage Waveform Machine LoadedMachine Loaded to 220 Amps AT 22 VDC Scope Settings Troubleshooting & Repair Typical SCR Gate Voltage Waveform Power MIG Control PC Board Removal and Replacement Procedure DescriptionRemoval and Replacement Procedure Control PC BoardFigure F.11 Control Board Mounting Power MIG 41TROUBLESHOOTING & REPAIRF-41 Wire Drive Assembly Removal and Replacement ProcedureWire Drive Assembly Removal and Replacement ProcedureTOC Power MIG SCR Output Rectifier Removal and Replacement Procedure SCR Output Rectifier Removal and Replacement Figure F.15 Right Heat Sink Lead Disconnection Power MIG Capacitor Bank Removal and Replacement Procedure Capacitor Bank Removal and Replacement Troubleshooting & Repair Removal and Replacement Main Transformer and Output ChokeTOC Power MIG FAN Motor Assembly Removal and Replacement Procedure FAN Motor Assembly Removal and Replacement Retest After Repair Troubleshooting and RepairWire Speed Range Open Circuit VoltagePower MIG Electrical Diagrams Section Power MIG 255 208/230V Wiring Diagram Entire Machine Code 10563 L10979Power MIG 255 230/460/575V Wiring Diagram Entire Machine Code 10583 L10980Power MIG 255 230/460/575 Wiring Diagram Entire Machine Code 10986 L11980Power MIG 255 208/230 Wiring Diagram Entire Machine Code 10990 L11979Control PC Board Schematic G3520-1D1 Control PC Board Assembly G3521-1 3521Display PC Board Schematic L10951 PowermigDisplay PC Board Assembly L10952-1 Lincoln Electric COSnubber PC Board Schematic S24374 24374 SSnubber PC Board Assembly M19248-1 00 ~.04SVM Error Reporting Form