Lincoln Electric SVM 119-A service manual Rectifier Assembly Test

Page 55

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F-4

TROUBLESHOOTING & REPAIR

F-4

 

 

 

 

TROUBLESHOOTING GUIDE - Observe all Safety Guidelines detailed throughout this manual

 

 

 

 

 

 

 

PROBLEMS

POSSIBLE AREAS OF

 

RECOMMENDED

 

(SYMPTOMS)

MISADJUSTMENTS(S)

 

COURSE OF ACTION

 

 

 

 

 

 

 

 

 

 

OUTPUT PROBLEMS

 

 

 

 

 

 

 

 

 

 

 

No Open Circuit Voltage output but

1. Check the input voltage at the

1.

Check for loose or broken con-

 

wire feeds normally when gun trig-

machine. Input voltage must

 

nections at the output terminals,

 

ger is pulled.

match the rating plate and the

 

the choke, the capacitor bank

 

 

 

reconnect panel.

 

and all heavy current carrying

 

 

 

 

 

leads.

 

 

 

 

2. The gun may be faulty. Check

 

 

 

 

 

 

or replace.

2.

Make sure that the transformer

 

 

 

 

 

secondary leads are

securely

 

 

 

 

 

connected to the SCR Rectifier

 

 

 

 

 

Assembly.

 

 

 

 

 

3.

Perform the SCR

Rectifier

 

 

 

 

 

Assembly Test.

 

 

 

 

 

4.

The control board may be faulty

 

 

 

 

 

- Replace.

 

 

 

 

 

 

 

Wire feeds but welding output is low

1. Make sure that the proper wire

1.

Check for loose or faulty con-

 

causing wire to "stub". Welds are

and procedures are being used.

 

nections of the heavy current

 

"cold". Machine cannot obtain full

 

 

carrying leads.

 

 

rated output of 200 amps at 28 volts.

2. Check gun and work cable for

 

 

 

 

 

 

loose or faulty connections.

2.

The output capacitor bank may

 

 

 

 

 

be faulty. Check for loose con-

 

 

 

 

 

nections at the capacitors. Also

 

 

 

 

 

check for leaky capacitors.

 

 

 

 

 

Replace if necessary.

 

 

 

 

 

 

WARNING: The liquid elec-

 

 

 

 

 

trolyte in these capacitors is

 

 

 

 

 

toxic. Avoid contact with any

 

 

 

 

 

portion of your body.

 

 

 

 

3.

Perform the SCR

Rectifier

 

 

 

 

 

Assembly Test.

 

 

 

 

 

4.

Perform the Main Transformer

 

 

 

 

 

Test.

 

 

 

 

 

5.

The control board may be faulty.

 

 

 

 

 

Replace.

 

 

 

 

 

 

 

 

 

CAUTION

If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, con- tact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed call 216- 383-2531 or 1-800-833-9353

WIRE-MATIC 255

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Contents Safety Depends on You WIRE-MATICFumes and Gases can be dangerous SafetyElectric Shock can kill ARC Rays can burnWelding Sparks can cause fire or explosion Cylinder may explode if damagedMay be dangerous Electric and MAG- Netic FieldsIii 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 Stacking Safety PrecautionsSelect Proper Location Input ConnectionsFuse 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 SectionGeneral Description Safety InstructionsWELDING, Cutting Recommended Processes and Equipment Design Features AdvantagesLimitations Machine CapabilityDuty Cycle Amps Volts 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 AccessoriesMagnum 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 Installation Optional K585-1 Timer KIT K585-1K363P READI-REEL Adapter Drive Roll Kits64 1.2mm Aluminum Feeding KIT K673-1 K468 8 Spool AdapterDual Cylinder Mounting KIT K671-1 Table of Contents Maintenance Section MaintenancePerform the following daily Routine and Periodic MaintenanceMaintenance GUN Tubes and Nozzles Cable CleaningContact TIP and GAS Nozzle Installation Drive Rolls and Guide TubesFigure 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 OperationWIRE-MATIC Table of Contents Troubleshooting & Repair Section Troubleshooting & Repair Recommended Course of Action HOW to USE Troubleshooting GuideElectric 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 Trolyte in these capacitors is Liquid elecPerform the Output Rectifier Test Description Main Transformer TestMaterials Needed 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 230/60 375 Wire Speed RangeOpen Circuit Voltage Input Volts/HertzWIRE-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
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