Lincoln Electric SVM 119-A PC Board Troubleshooting Procedures, Electric Shock can kill

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ATTENTION Static-Sensitive Devices Handle only at Static-Safe Workstations
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TROUBLESHOOTING & REPAIR

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PC BOARD TROUBLESHOOTING PROCEDURES

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WARNING

ELECTRIC SHOCK can kill.

Have an electrician install and service this equipment. Turn the input power OFF at the fuse box before work- ing on equipment. Do not touch electrically hot parts.

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CAUTION: Sometimes machine failures appear to be due to PC board failures. These problems can sometimes be traced to poor electrical connections. To avoid problems when troubleshooting and replacing PC boards, please use the following procedure:

1.Determine to the best of your technical abil- ity that the PC board is the most likely com- ponent causing the failure symptom.

2.Check for loose connections at the PC board to assure that the PC board is proper- ly connected.

3.If the problem persists, replace the suspect PC board using standard practices to avoid static electrical damage and electrical shock. Read the warning inside the static resistant bag and perform the following pro-

cedures:

P.C. Board can be dam- aged by static electricity.

- Remove your body’s static charge before opening the static-shielding bag. Wear an anti-static wrist strap. For safety, use a 1 Meg ohm resistive cord connected to a grounded part of the equipment frame.

- If you don’t have a wrist strap, touch an unpainted, grounded, part of the equip-

ment frame. Keep touching the frame to pre- vent static build-up. Be sure not to touch any electrically live parts at the same time.

-Tools which come in contact with the P.C. Board must be either conductive, anti-static or static-dissipative.

- Remove the P.C. Board from the static- shielding bag and place it directly into the equipment. Don’t set the P.C. Board on or near paper, plastic or cloth which could have a static charge. If the P.C. Board can’t be installed immediately, put it back in the static- shielding bag.

-If the P.C. Board uses protective shorting jumpers, don’t remove them until installation is complete.

-If you return a P.C. Board to The Lincoln Electric Company for credit, it must be in the static-shielding bag. This will prevent further damage and allow proper failure analysis.

4.Test the machine to determine if the failure symptom has been corrected by the replacement PC board.

NOTE: It is desirable to have a spare (known good) PC board available for PC board trou- bleshooting.

NOTE: Allow the machine to heat up so that all electrical components can reach their oper- ating temperature.

5.Remove the replacement PC board and substitute it with the original PC board to recreate the original problem.

a.If the original problem does not reappear by substituting the original board, then the PC board was not the problem. Continue to look for bad connections in the control wiring harness, junction blocks, and terminal strips.

b.If the original problem is recreated by the substitution of the original board, then the PC board was the problem. Reinstall the replacement PC board and test the machine.

6.Always indicate that this procedure was fol- lowed when warranty reports are to be sub- mitted.

NOTE: Following this procedure and writing on the warranty report, “INSTALLED AND SWITCHED PC BOARDS TO VERIFY PROB- LEM,” will help avoid denial of legitimate PC board warranty claims.

WIRE-MATIC 255

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Contents Safety Depends on You WIRE-MATICElectric Shock can kill SafetyARC Rays can burn Fumes and Gases can be dangerousWelding Sparks can cause fire or explosion Cylinder may explode if damagedIii Electric and MAG- Netic FieldsMay be dangerous Sûreté Pour Soudage a L’Arc Précautions DE SûretéWIRE-MATIC Table of Contents Table of Contents Table of Contents Installation Section InstallationTechnical Specifications Wire-Matic-255 Select Proper Location Safety PrecautionsInput Connections StackingFuse and Wire Sizes Connect Shielding GAS Figure A.4 Input Gas Supply Connections Reconnect ProcedureFigure A.5 Reconnect Diagram For 208/230/1/60 Machines Connections Connect Output ComponentsGUN and Cable Installation Wire Size Conversion PartsWIRE-MATIC Operation Table of Contents Operation SectionWELDING, Cutting Safety InstructionsGeneral Description Recommended Processes and Equipment Design Features AdvantagesDuty Cycle Amps Volts Machine CapabilityLimitations Figure B.1 Operator Controls Controls and SettingsFigure B.2 Wire Reel Loading Using the Wire Drive RollFeeding Electrode Operating Steps Setting Idle Roll PressureMaking a Weld WIRE-MATIC Table of Contents Accessories Section AccessoriesK672-1 Spool GUN Adapter KIT OPTIONS/ACCESSORIESMagnum GUN Connection KIT Optional K466-6 Making a Weld with the Spool GUN Adapter K672-1 Installed Timer KIT Installation Optional K585-1 Timer KIT K585-164 1.2mm Aluminum Feeding KIT K673-1 Drive Roll KitsK468 8 Spool Adapter K363P READI-REEL AdapterDual Cylinder Mounting KIT K671-1 Table of Contents Maintenance Section MaintenancePerform the following daily Routine and Periodic MaintenanceMaintenance Contact TIP and GAS Nozzle Installation Cable CleaningDrive Rolls and Guide Tubes GUN Tubes and NozzlesFigure D.2 Liner maintenance Liner Removal ReplacementTo open up the handle GUN Handle DisassemblyDescription English Size Metric Size WIRE-MATIC Theory of Operation Table of Contents Theory of Operation SectionTransformer Input Line Voltage and MainFeedback Control Output RectificationFigure E.4 Constant Voltage Output Constant Voltage OutputFeedback Wire Drive MotorThermal Protection Figure E.6 SCR Operation SCR Operation WIRE-MATIC Table of Contents Troubleshooting & Repair Section Troubleshooting & RepairRecommended Course of Action HOW to USE Troubleshooting GuideBoard can be dam- aged by static electricity PC Board Troubleshooting ProceduresElectric Shock can kill Main Transformer Rectifier Assembly Test To Section TOC SCR Rectifier Perform the Wire Drive Motor Trolyte in these capacitors is Liquid elecPerform the Output Rectifier Materials Needed Main Transformer TestTest Description ON/OFF Power Switch will be hot during these tests Main Transformer Test Test ProcedureLead Plug Location Static SCR Rectifier Assembly Test Leads Figure F.4 SCR 1 Test Points Active SCR Rectifier Assembly Test Leads SCR connections Figure F.7 SCR Tester CircuitWire Drive Motor and Tachometer Feedback Test Wire Drive Motor and Tachometer Feedback Test Test Procedure Test for Feedback Voltage to the Control Board Test for Supply Voltage to TachometerNormal Open Circuit Voltage Waveform Scope SettingsTypical Output Voltage Waveform Machine Loaded Machine Loaded to 250 Amps AT 26 VDC Scope SettingsMachine Loaded to 220 Amps AT 22 VDC Scope Settings Troubleshooting & Repair Typical SCR Gate Voltage Waveform Removal and Replacement Procedure Control PC Board Removal and ReplacementRemoval and REPLACE- Ment Procedure Wire Drive Assembly Removal and Replacement Figure F.11 Wire Drive Assembly Removal ProcedureSCR Output Rectifier Removal & Replacement Disconnection Heat Sink Lead Right side heat sink See Figure F.14Capacitor Bank Removal and Replacement Components Bank Removal ReplacementMain Transformer Removal and Replacement Power Switch FAN Motor and FAN Removal and Replacement Figure F.16 Fan Motor and Fan Removal Components FAN Motor and FAN Removal and Replacement ProcedureTroubleshooting & Repair Open Circuit Voltage Wire Speed RangeInput Volts/Hertz 230/60 375WIRE-MATIC Table of Contents Electrical Diagrams Section WIRE-MATIC Wiring Diagram 208/230 Code Electrical DiagramsWiring Diagram 230/460/575 Code Wire Matic 255 230 / 460Control PC Board G2803 Schematic Control PC Board G2803 Layout Wirematic 255 Control