Lincoln Electric SP-250 service manual Figure F.7 SCR Tester Circuit and SCR connections

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F-24

TROUBLESHOOTING & REPAIR	F-24

ACTIVE SCR RECTIFIER ASSEMBLY TEST

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7.Connect the Tester to the SCR 1 as shown in Figure F.7.

a.Connect Tester lead (A) to the anode.

b.Connect Tester lead (C) to the cathode.

c.Connect Tester lead (G) to the gate.

FIGURE F.7 - SCR Tester Circuit and SCR connections.

8. Close switch SW-1.

NOTE: Switch SW-2 should be open.

9.Read meter for zero voltage.

a.If the voltage reading is higher than zero, the SCR is shorted.

10.Close or keep closed switch SW-1

11.Close switch SW-2 for 2 seconds and release and read meter.

a.If the voltage is 3 - 6 volts while the switch is closed and after the switch is open, the SCR is functioning.

b.If the voltages is 3-6 volts only when the switch is closed or there is no voltage when the switch is closed, the SCR is defective.

NOTE: Be sure battery is functioning properly. A low battery can affect the results of the test. Repeat Battery Test Procedure in Step 6 if needed.

12.Open switch SW-1.

13.Reconnect the Tester leads. See Figure F.7.

a.Connect Tester lead (A) to the cathode.

b.Connect Tester lead (C) to the anode.

c.Disconnect Test lead (G) from the gate.

14.Close switch SW-1.

15.Read meter for zero voltage.

a.If the voltage is zero, the SCR is functioning.

b.If the voltage is higher than zero, the SCR is shorted.

16.Perform the Active Test Procedure outlined in Steps 5-13for SCR 2.

17.Replace all SCR assemblies that do not pass the above tests.

18.Replace all Molex Plugs onto the Control Board and connect leads X2 and X3.

IDEALARC SP-250

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Contents Idealarc SP-250 Safety Depends on YouIdealarc SP-250 ARC Welding can be hazardousCylinder may explode if damaged Iii Electric and MAG- Netic FieldsSûreté Pour Soudage a L’Arc Précautions DE SûretéTable of Contents Installation Storage Operating Depth Weight GUNHeight Stacking Safety PrecautionsSelect Proper Location Input ConnectionsInput Power Connections Ground Connections Fuse and Wire SizesFigure A.3 Ground Connection For 230/460/575 Volt Models Connect Shielding GASSide Reconnect ProcedureReturn to Section TOC Output Polarity Connection GUN Liner & Contact TIP InstallationInstall the Work Clamp Connect Output ComponentsFigure A.9 European Style Connector GUN & Cable InstallationOperation Electric Shock can kill Safety InstructionsAdditional Safety Precautions General DescriptionRecommended Processes System includes the following featuresOperational ControlsPower Source Features Design FeaturesUnit Features Wire Feeder FeaturesDuty Amps Volts Cycle Machine CapabilityLimitations Figure B.1 SP-250 Control Panel Keys Controls and SettingsProcess WIRE/GAS KEY Arrow KEY Operation When Used withArrow KEY Operation When Used with Manual KEY Arrow KEY Operation When Used with Auto KEYRight arrow keys Do not function Arrow KEY Operation When Used with Spot KEYArrow KEY Operation When Used with Stitch KEY Left arrow keys Do not functionStep Trigger Interlock Keys Figure B.5 Using the Toggle FunctionOperating Steps RUN-IN ModeChanging RUN-IN Mode Codes 10001 and Above Making a Weld in Auto ModeTo make an arc spot plug weld Using the 4-STEP Interlock Function in Auto ModeMaking a Spot Weld in Auto Mode Using the GUN Trigger Switch Using the GUN Thumb Switch Magnum SP-250 onlyUsing the Wire Drive Roll Making a Stitch Weld in Auto ModeTo mount 10 to 30 lb. spools 8 and 12 diameter Loading the Wire ReelFeeding Electrode Setting Idle Roll PressureAccessories Spool GUN Module Board Installation Options / AccessoriesSpool GUN Adapter KIT Installation Figure C.2 Spool Gun Module Board Installation Spool GUN Connection BOX InstallationFigure C.5 Spool Gun Connect Spool GUN ConnectionFigure C.6 Spool Gun Connection Spool GUN Installation to OLD K531 KITMaintenance Routine and Periodic MaintenanceControl Board Choke Fan Assembly Main Transformer Theory of Operation Former Power Supply OperationInput Line Voltage and Main Trans Back Control Output Rectification and FeedFigure E.4 Constant Voltage Output Constant Voltage OutputFigure E.5 Wire Drive Motor and Feedback Wire Drive Motor and FeedbackThermal Protection Figure E.6 SCR Operation SCR OperationTroubleshooting & Repair Recommended Course of Action HOW to USE Troubleshooting GuideBoard can be dam- aged by static electricity PC Board Troubleshooting ProceduresOutput Problems Warn Troubleshooting & Repair Function Problems Troubleshooting & Repair Wire Feeding Problems Portion of your body Liquid elecTrolyte in these capacitors is Toxic. Avoid contact with anyTroubleshooting & Repair On Screen Error Message Message Explanation Explanation of Prompting and Error MessagesXxxx Explanation of Prompting and Error Messages CONT’DOn Screen Error Message Current Overload Reduce Output Press ANY KEY to Stop Message Materials Needed Main Transformer TestTest Description Main Transformer Test Test Procedure From Expected Lead Voltage Lead Plug Location#206 4J6 #208 16J6 #209 7J6 G1992 Code 9402 only Troubleshooting & Repair 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 and SCR connections 25F-25 SP-250 Keypad Resistance TestFigure F.9 Plug J2 Test Points Figure F.8A Plug J2 Location on G2252 PC Control BoardTable F.1 SP-250 Keypad Resistance Tests Test Points KEY Pressed Maximum Allowable27F-27 Wire Drive Motor and Tachometer Feedback Test Figure F.10A Plug J5 Location on G2252 PC Control Board Wire Drive Motor and Tachometer Feedback Test Test ProcedurePull the gun trigger #206B 4J6 #515B 1J6 #555 2J6 #541 6J6 #539 3J6Test 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 Materials Needed Control PC Board Removal and ReplacementTroubleshooting & Repair Keypad Removal and Replacement Keypad Removal and Replacement Procedure Wire Drive Assembly Removal and Replacement Figure F.13 Wire Drive Assembly Removal Wire Drive Assembly Removal and Replacement Procedure43F-43 SCR Output Rectifier RemovalFigure F.14 Heat Sink lead discon- nection Capacitor Bank Removal and Replacement Capacitor Bank Removal and Replacement Procedure Main Transformer Removal and Replacement Power Switch FAN Motor and FAN Removal and Replacement Figure F.18 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/HertzTable of Contents Electrical Diagrams G1992 Control PC Board Identification X9 . . . . . .IC-CMOS,UNDERVOLT-SENSING,RESET,MCU Idealarc SP-250 Electrical Diagrams G2252 Control PC Board TOC OCI2,OCI3 Optocoupler Triac Driver Idealarc SP-250 Electrical Diagrams SP-250 230/460/575V Wiring Diagram Wiring Diagram for Code 9546Thumb Switch Wiring Diagram for Code 9723Improper Lincoln Electric. 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