Static SCR Rectifier Assembly Test | Lincoln Electric SVM 119-A

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F-13	TROUBLESHOOTING & REPAIR	F-13
	TROUBLESHOOTING & REPAIR

STATIC SCR RECTIFIER ASSEMBLY TEST

WARNING

Service and repair should be performed only by Lincoln Electric factory trained per- sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the 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 perform the tests/repairs safely, contact the Lincoln Electric service department for technical troubleshooting assistance before you proceed.

Call (216) 383-2531 or (800) 833-9353 (WELD).

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TEST DESCRIPTION

This test is used to quickly determine if an SCR or diode is shorted or "leaky." See the Machine Waveform Section in this manual for normal and abnormal output waveforms.

MATERIALS NEEDED

Analog Ohmmeter (Multimeter).

Wire-Matic 255 wiring diagrams (See Electrical Diagrams Section of this Manual). 5/16" Nut Driver.

1/2" Open end or socket wrench.

WIRE-MATIC 255

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Lincoln Electric SVM 119-A service manual Static SCR Rectifier Assembly Test, Test Description

Contents

WIRE-MATIC Safety Depends on You Safety Electric Shock can killARC Rays can burn Fumes and Gases can be dangerous Cylinder may explode if damaged Welding Sparks can cause fire or explosion May be dangerous Electric and MAG- Netic FieldsIii Précautions DE Sûreté Sûreté Pour Soudage a L’Arc WIRE-MATIC Table of Contents Table of Contents Installation Table of Contents Installation Section Technical Specifications Wire-Matic-255 Safety Precautions Select Proper LocationInput Connections Stacking Fuse and Wire Sizes Connect Shielding GAS Reconnect Procedure Figure A.4 Input Gas Supply Connections Figure A.5 Reconnect Diagram For 208/230/1/60 Machines Connect Output Components Connections Wire Size Conversion Parts GUN and Cable Installation WIRE-MATIC Table of Contents Operation Section Operation General Description Safety InstructionsWELDING, Cutting Design Features Advantages Recommended Processes and Equipment Limitations Machine CapabilityDuty Cycle Amps Volts Controls and Settings Figure B.1 Operator Controls Using the Wire Drive Roll Figure B.2 Wire Reel Loading Feeding Electrode Setting Idle Roll Pressure Operating Steps Making a Weld WIRE-MATIC Accessories Table of Contents Accessories Section Magnum GUN Connection KIT Optional K466-6 OPTIONS/ACCESSORIESK672-1 Spool GUN Adapter KIT Making a Weld with the Spool GUN Adapter K672-1 Installed Timer KIT K585-1 Timer KIT Installation Optional K585-1 Drive Roll Kits 64 1.2mm Aluminum Feeding KIT K673-1K468 8 Spool Adapter K363P READI-REEL Adapter Dual Cylinder Mounting KIT K671-1 Maintenance Table of Contents Maintenance Section Routine and Periodic Maintenance Perform the following daily Maintenance Cable Cleaning Contact TIP and GAS Nozzle InstallationDrive Rolls and Guide Tubes GUN Tubes and Nozzles Liner Removal Replacement Figure D.2 Liner maintenance GUN Handle Disassembly To open up the handle Description English Size Metric Size WIRE-MATIC Table of Contents Theory of Operation Section Theory of Operation Input Line Voltage and Main Transformer Output Rectification Feedback Control Constant Voltage Output Figure E.4 Constant Voltage Output Wire Drive Motor Feedback Thermal Protection SCR Operation Figure E.6 SCR Operation WIRE-MATIC Troubleshooting & Repair Table of Contents Troubleshooting & Repair Section HOW to USE Troubleshooting Guide Recommended Course of Action Electric Shock can kill PC Board Troubleshooting ProceduresBoard can be dam- aged by static electricity Main Transformer Rectifier Assembly Test To Section TOC SCR Rectifier Perform the Wire Drive Motor Liquid elec Trolyte in these capacitors is Perform the Output Rectifier Test Description Main Transformer TestMaterials Needed Main Transformer Test Test Procedure ON/OFF Power Switch will be hot during these tests Lead Plug Location Static SCR Rectifier Assembly Test Leads Figure F.4 SCR 1 Test Points Active SCR Rectifier Assembly Test Leads Figure F.7 SCR Tester Circuit SCR connections Wire Drive Motor and Tachometer Feedback Test Wire Drive Motor and Tachometer Feedback Test Test Procedure Test for Supply Voltage to Tachometer Test for Feedback Voltage to the Control Board Scope Settings Normal Open Circuit Voltage Waveform Machine Loaded to 250 Amps AT 26 VDC Scope Settings Typical Output Voltage Waveform Machine Loaded Machine Loaded to 220 Amps AT 22 VDC Scope Settings Troubleshooting & Repair Typical SCR Gate Voltage Waveform Control PC Board Removal and Replacement Removal and Replacement Procedure Removal and REPLACE- Ment Procedure Wire Drive Assembly Removal and Replacement Procedure Figure F.11 Wire Drive Assembly Removal SCR Output Rectifier Removal & Replacement Right side heat sink See Figure F.14 Disconnection Heat Sink Lead Capacitor Bank Removal and Replacement Bank Removal Replacement Components Main Transformer Removal and Replacement Power Switch FAN Motor and FAN Removal and Replacement FAN Motor and FAN Removal and Replacement Procedure Figure F.16 Fan Motor and Fan Removal Components Troubleshooting & Repair Wire Speed Range Open Circuit VoltageInput Volts/Hertz 230/60 375 WIRE-MATIC Table of Contents Electrical Diagrams Section WIRE-MATIC Electrical Diagrams Wiring Diagram 208/230 Code Wire Matic 255 230 / 460 Wiring Diagram 230/460/575 Code Control PC Board G2803 Schematic Wirematic 255 Control Control PC Board G2803 Layout