Lincoln Electric PRECISION TIG SVM186-A Service Manual
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Lincoln Electric PRECISION TIG SVM186-A Service Manual

Lincoln Electric PRECISION TIG SVM186-A Service Manual

Lincoln electric welder user manual
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PRECISION TIG 225
Safety Depends on You
Lincoln arc welding and cutting
equipment is designed and built
with safety in mind.
However,
your
overall
safety
can
increased by proper installation
. . . and thoughtful operation on
your part.
DO NOT INSTALL,
OPERATE OR REPAIR THIS
EQUIPMENT WITHOUT READ-
ING THIS MANUAL AND THE
SAFETY PRECAUTIONS CON-
TAINED THROUGHOUT.
most importantly, think before you
act and be careful.
• Sales and Service through Subsidiaries and Distributors Worldwide •
Cleveland, Ohio 44117-1199 U.S.A. TEL: 1.888.935-3877 FAX: 216.486.1751 WEB SITE: www.lincolnelectric.com
RETURN TO MAIN MENU
RETURN TO MAIN INDEX
For use with machine code numbers:
be
And,

SERVICE MANUAL

• World's Leader in Welding and Cutting Products •
SVM186-A
October, 2008
®
11317, 11318, 11319
(11320 Ready-Pak)
(11321 Ready-Pak w/Cart)
Copyright © Lincoln Global Inc.

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Summary of Contents for Lincoln Electric PRECISION TIG SVM186-A

  • Page 1: Service Manual

    PRECISION TIG 225 Safety Depends on You Lincoln arc welding and cutting equipment is designed and built with safety in mind. However, your overall safety increased by proper installation . . . and thoughtful operation on your part. DO NOT INSTALL, OPERATE OR REPAIR THIS EQUIPMENT WITHOUT READ- ING THIS MANUAL AND THE...
  • Page 2 “Safety in Welding & Cutting - ANSI Standard Z49.1” from the American Welding Society, P.O. Box 351040, Miami, Florida 33135 or CSA Standard W117.2-1974. A Free copy of “Arc Welding Safety” booklet E205 is available from the Lincoln Electric Company, 22801 St. Clair Avenue, Cleveland, Ohio 44117-1199. 1.a. Turn the engine off before troubleshooting and maintenance work unless the maintenance work requires it to be running.

  • Page 3: Electric Shock Can Kill

    ELECTRIC SHOCK can kill. 3.a. The electrode and work (or ground) circuits are electrically “hot” when the welder is on. Do not touch these “hot” parts with your bare skin or wet clothing. Wear dry, hole-free gloves to insulate hands.
  • Page 4 WELDING and CUTTING SPARKS can cause fire or explosion. 6.a. Remove fire hazards from the welding area. If this is not possible, cover them to prevent welding sparks from Remember that welding sparks materials from welding can easily go through small cracks and openings to adjacent areas.
  • Page 5 PRÉCAUTIONS DE SÛRETÉ Pour votre propre protection lire et observer toutes les instructions et les précautions de sûreté specifiques qui parraissent dans ce manuel aussi bien que les précautions de sûreté générales suiv- antes: Sûreté Pour Soudage A LʼArc 1. Protegez-vous contre la secousse électrique: a.
  • Page 6 (89/336/EEC). It was manufactured in conformity with a national standard that implements a harmonized standard: EN 60974-10 Electromagnetic Compatibility (EMC) Product Standard for Arc Welding Equipment. It is for use with other Lincoln Electric equipment. It is designed for industrial and professional use. Introduction All electrical equipment generates small amounts of electromagnetic emission.
  • Page 7 SAFETY Electromagnetic Compatibility (EMC) The size of the surrounding area to be considered will depend on the structure of the building and other activities that are taking place. The surrounding area may extend beyond the boundaries of the premises. Methods of Reducing Emissions Mains Supply Welding equipment should be connected to the mains supply according to the manufacturer’s recommen- dations.
  • Page 8 - MASTER TABLE OF CONTENTS FOR ALL SECTIONS - RETURN TO MAIN INDEX RETURN TO MAIN MENU Page Safety ................i-iv Installation .

  • Page 9: Table Of Contents

    TABLE OF CONTENTS - INSTALLATION SECTION Installation ................A-1 Technical Specifications .

  • Page 10: Output Range

    Use a Super Lag type fuse or circuit breaker with a delay in tripping action. Models with NEMA 6-50P plug may be used with a 50 amp protected 6-50R receptacle, or with a maximum 70 amp protected 6-50R receptacle if dedicated for the welder. INSTALLATION...

  • Page 11: Installation

    TECHNICAL SPECIFICATIONS - CANADIAN (K2533-2), INTERNATIONAL K2534-1) Voltage/Phase/Freq. 460/575/1/60 Voltage/Phase/Freq. 380/400-415/1/50/60 Max. OCV. 75 V (AC) 66 V (DC) Process Duty Cycle** SMAW 100% GTAW 100% Inputs and ratings include a 6 amp rated load on the 115vac receptacle. Based on a 10 minute cycle. MODEL HEIGHT Machine Only...

  • Page 12: Safety Precautions

    TIG® 225 should be kept to a minimum. Failure to observe these precautions can result in excessive operating temperatures and nuisance shutdown. GRINDING Do not direct grinding particles towards the welder. An abundance of conductive material can cause mainte- nance problems. STACKING PRECISION TIG®...

  • Page 13: Machine Grounding And High Frequency Interference Protection

    Keeping these contributing factors in mind, installing equipment per the following instructions should minimize problems. 1. Keep the welder power supply lines as short as possi- ble and enclose as much of them as possible in rigid metallic conduit or equivalent shielding for a distance of 50 feet (15.2m).

  • Page 14: Input Reconnect Procedure

    CAUTION Failure to follow these instructions can cause immediate failure of components within the welder and void machineʼs warranty. ----------------------------------------------------------------------- Multiple voltage models are shipped connected for the highest voltage.

  • Page 15: Work Cable Connections

    Twist-Mate quick connect plug into the Electrode/Gas Output Receptacle on the front of the welder and turn it clockwise until it is tight. This is a Twist-Mate quick connect terminal and also provides the gas connection for the shielding gas to the torch.
  • Page 16 NOTES PRECISION TIG® 225...
  • Page 17 TABLE OF CONTENTS - OPERATION SECTION Operation ................B-1 Safety Precautions .

  • Page 18: Operation

    SAFETY PRECAUTIONS Read and understand this entire section before operat- ing the machine. WARNING ELECTRIC SHOCK can kill. • Do not touch electrically live parts or electrode with skin or wet cloth- ing. • Insulate yourself from work and ground. •...

  • Page 19: Product Description

    PRODUCT DESCRIPTION The PRECISION TIG® 225 is a member of our field acclaimed PRECISION TIG® family of industrial arc welding power sources. Premium features include: 1. Precise constant current output. 2. Full range square wave AC/DC TIG (GTAW) welding. 3. Enhanced version of the patented Micro-Start II™ Technology for its lower Minimum(5 amps) to higher Maximum (230 amps) output control range.

  • Page 20: Controls And Settings

    CONTROLS AND SETTINGS All operator controls and adjustments are located on the front of the PRECISION TIG 225. Refer to Figure B.1 and corresponding explanations. CONTROL FUNCTIONALITY 1. POWER SWITCH – Input line switch turns input power ON or OFF, as indicated by the on or off sta- tus of the front panel digital display (See Item 6, also see the following page for Power-Up Sequence).

  • Page 21: Power-Up Sequence

    TIG torch when TIG welding. 12. WORK CABLE - This 10ft.(3.05m) cable with work clamp is factory connected to the welder and its clamp is connected to the work piece to complete the welding circuit. Refer to Machine Grounding...

  • Page 22: Case Rear Components

    CASE REAR COMPONENTS 1. INPUT CABLE– This #6-3 (208/230V) or #12-3 (380V and higher) heavy duty cable with cable clamp is factory installed on all models. The Domestic models (208/230V) also are equipped with a NEMA 6-50P plug. 2. GAS INPUT CONNECTOR – This is a 5/8-18 right- hand thread female fitting for connection of input gas supply.

  • Page 23: Operating Steps

    OPERATING STEPS WELDING IN TIG MODE 1. Connect the TIG torch and cable Twist-Mate™ quick connect plug to the Electrode/Gas output recepta- cle. This receptacle also contains an integral gas connection for the torch. Connect the work clamp to the work piece. 2.

  • Page 24: Remote Control Operation

    When the welder is in the stick mode a remote control has no effect and is not used. It is important to note that, in some cases, the tungsten will not start an arc at the minimum current because the tungsten may be too large or cold.
  • Page 25 WELDING IN STICK MODE 1. Put the electrode holder and cable quick connect plug into the electrode output receptacle. Turn clock- wise until tight. Connect the work clamp to the work piece. 2. Set the TIG/STICK switch to “STICK”. 3. Set the Polarity Switch to the weld mode desired for the type of electrode being used (most commonly DC+).
  • Page 26 B-10 B-10 NOTES PRECISION TIG® 225...
  • Page 27 TABLE OF CONTENTS - ACCESSORIES SECTION Accessories ................C-1 Standard Equipment Packages .

  • Page 28: Accessories

    STANDARD EQUIPMENT PACKAGES The PRECISION TIG® 225 will be available in two Factory-Configured Welding Packages: 1. PRECISION TIG® 225 Ready-Pak (K2535-1) • 208/230/1/60 Machine (K2533-1) • 9 ft. (2.7m) Input Cable with NEMA 6-50P Plug* • NEMA 6-50R Receptacle • Integrated 10 ft.(3.1m)Work Lead w/Clamp* •...

  • Page 29: Factory Installed Options

    FACTORY INSTALLED OPTIONS The PRECISION TIG® 225 will be available in two Factory-Configured Welding Packages: 1. PRECISION TIG® 225 Ready-Pak (K2535-1) • 208/230/1/60 Machine (K2533-1) • 9 ft. (2.7m) Input Cable with NEMA 6-50P Plug* • NEMA 6-50R Receptacle • Integrated 10 ft.(3.1m)Work Lead w/Clamp* •...

  • Page 30: Field Installed Options

    FIELD INSTALLED OPTIONS The following Options/Accessories are available for the PRECISION TIG® 225: • K2348-1 Under-Storage Cart Includes a front magnetic latch storage drawer and rear storage bin on a single bottle undercarriage. (L12225 Installation Instructions included) • K870 Foot Amptrol Single pedal foot activation of arc start switch and output control, with 25 ft.(7.6m) plug cable.
  • Page 31 TABLE OF CONTENTS - MAINTENANCE SECTION Maintenance ................D-1 Safety Precautions .
  • Page 32 • Arc Starter/Spark Gap Assembly • PC Boards • Fan Blades 3. Inspect welder output and control cables for fraying, cuts, and bare spots. 4. Keep TIG torch and cables in good condition. 5. Clean air louvers to ensure proper air flow and cool- ing.
  • Page 33 TABLE OF CONTENTS-THEORY OF OPERATION SECTION Theory of Operation ..............E-1 General Description .

  • Page 34: General Description

    THEORY OF OPERATION FIGURE E.2 - General Description & Input Power Circuit INPUT POWER SWITCH BYPASS ASBLY 115 VAC Receptacle Circuit Breaker Protected AUTO BALANCE GENERAL DESCRIPTION The PRECISION TIG® 225 is a member of our field acclaimed PRECISION TIG® family of industrial arc welding power sources.
  • Page 35 THEORY OF OPERATION FIGURE E.2 - Output Rectification & Feedback Control INPUT POWER SWITCH BYPASS ASBLY 115 VAC Receptacle Circuit Breaker Protected OUTPUT RECTIFICATION FEEDBACK CONTROL The AC output from the main transformer secondary is rectified and controlled through the SCR bridge. Output current is sensed at the shunt as a low voltage signal and fed back to the control board.

  • Page 36: Theory Of Operation

    THEORY OF OPERATION FIGURE E.2 - High Voltage/High Frequency Circuit. MAIN TRANSFORMER INPUT POWER SWITCH BYPASS ASBLY 115 VAC Receptacle Circuit Breaker Protected REMOTE RECEPTACLE HIGH VOLTAGE / HIGH FREQUENCY CIRCUIT The control board passes the 115VAC voltage to the primary of the high voltage transformer.

  • Page 37: Dc Welding Output

    THEORY OF OPERATION DC WELDING OUTPUT When the polarity switch is placed in either DC position, the AC voltage from the main transformer secondary is applied to the SCR bridge. The SCR bridge and choke circuits are connected in a conventional full wave bridge and filter configuration, resulting in a controlled DC output.

  • Page 38: Ac Welding Output

    THEORY OF OPERATION AC WELDING OUTPUT Rotating the polarity switch to the AC position changes the welding power circuit. One lead (X1) of the main transformer secondary is connected to the machine output work terminal. The other secondary lead (X2) is con- nected to one of the AC connections on the SCR bridge.

  • Page 39: Scr Operation

    THEORY OF OPERATION SCR OPERATION A silicon controlled rectifier (SCR) is a three terminal device used to control rather large currents to a load. An SCR acts very much like a switch. When a gate signal is applied to the SCR it is turned ON and there is current flow from anode to cathode.

  • Page 40: Protective Circuits

    OVERLOAD PROTECTION The machine is electronically protected from producing excessively high output currents. The output is limited If the welder to 200 amps. 115 VAC RECEPTACLE The auxiliary receptacle is circuit breaker protected.
  • Page 41 TABLE OF CONTENTS - TROUBLESHOOTING AND REPAIR Troubleshooting and Repair...F-1 How to Use Troubleshooting Guide ...F-2 PC Board Troubleshooting Procedures and Replacement ...F-3 Troubleshooting Guide ...F-4 Test Procedures High Frequency Circuit Disable Procedure ...F-15 T1 Transformer Test ...F-17 Static SCR Test ...F-21 Active SCR Test ...F-25 Oscilloscope Waveforms Normal Open Circuit Voltage Waveform-AC TIG Mode ...F-29...

  • Page 42: Troubleshooting And Repair

    TROUBLESHOOTING AND REPAIR HOW TO USE TROUBLESHOOTING GUIDE Service and Repair should only be performed by Lincoln Electric Factory Trained Personnel. Unauthorized repairs performed on this equipment may result in danger to the technician and machine operator and will invalidate your factory warranty. For your safety and to avoid Electrical Shock, please observe all safety notes and precautions detailed throughout this manual.

  • Page 43: Pc Board Troubleshooting Procedures

    - If the PC board uses protective shorting jumpers, don’t remove them until installation is complete. - If you return a PC board to The Lincoln Electric Company for credit, it must be in the static-shielding bag. This will prevent further damage and allow prop- er failure analysis.
  • Page 44 Stick or TIG modes. 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 1-888-935-3877. POSSIBLE AREAS OF...
  • Page 45 - fan is working normally. 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 1-888-935-3877. POSSIBLE AREAS OF...
  • Page 46 TIG mode. 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 1-888-935-3877.
  • Page 47 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 1-888-935-3877. POSSIBLE AREAS OF...
  • Page 48 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 1-888-935-3877. POSSIBLE AREAS OF...
  • Page 49 The arc "pulsates" when AC TIG welding. 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 1-888-935-3877. POSSIBLE AREAS OF...
  • Page 50 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 1-888-935-3877. POSSIBLE AREAS OF...
  • Page 51 Specifications in the Installation Chapter. 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 1-888-935-3877. POSSIBLE AREAS OF...
  • Page 52 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 1-888-935-3877. POSSIBLE AREAS OF...
  • Page 53 The end of the tungsten electrode melts away. 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 1-888-935-3877. POSSIBLE AREAS OF...
  • Page 54 Stick mode. 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 1-888-935-3877.

  • Page 55: High Frequency Circuit Disable Procedure

    TROUBLESHOOTING AND REPAIR HIGH FREQUENCY CIRCUIT DISABLE PROCEDURE Service and repair should be performed by only Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precautions detailed throughout this manual.
  • Page 56 F-16 TROUBLESHOOTING AND REPAIR HIGH FREQUENCY CIRCUIT DISABLE PROCEDURE (continued) FIGURE F.1 – SPARK GAP ASSEMBLY LEFT SIDE OF MACHINE PROCEDURE 1. Remove input power to the TIG 225 machine. 2. Using the 3/8” nutdriver remove the right side panel. 3.

  • Page 57: T1 Transformer Test

    F-17 TROUBLESHOOTING AND REPAIR Service and repair should be performed by only Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precautions detailed throughout this manual.
  • Page 58 F-18 TROUBLESHOOTING AND REPAIR T1 TRANSFORMER TEST (continued) FIGURE F.2 – PROCEDURE 1. Remove main supply power to the machine. 2. Using the 3/8” nutdriver remove the case wrap- around cover. 3. Locate plugs J3 and J4 on the control board. See Figure F.2. 4.
  • Page 59 F-19 TROUBLESHOOTING AND REPAIR T1 TRANSFORMER TEST (continued) PROCEDURE 6. If all of the secondary voltages are correct the T1 transformer is functioning properly. A. If all of the secondary voltages are missing or incorrect make certain that the correct input voltage is being applied to the correct primary leads.
  • Page 60 F-20 F-20 NOTES PRECISION TIG® 225...

  • Page 61: Static Scr Test

    F-21 TROUBLESHOOTING AND REPAIR Service and repair should be performed by only Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precautions detailed throughout this manual.
  • Page 62 F-22 TROUBLESHOOTING AND REPAIR STATIC SCR TEST (continued) FIGURE F.3 – Plug J2 Location on Control Board TEST PROCEDURE 1. Remove main supply power to the TIG 225 and remove the case wrap-around cover. 2. Locate and remove plug J2 from the control board.
  • Page 63 F-23 TROUBLESHOOTING AND REPAIR CASE COVER REMOVAL AND REPLACEMENT PROCEDURE (continued) SCR1 ANODE SCR1 CATHODE/SCR2 ANODE TEST PROCEDURE (continued) 3. Using an analog ohmmeter test the resistance from anode to cathode of SCR1. Reverse the meter leads and check from cathode to anode of SCR1.
  • Page 64 F-24 F-24 NOTES PRECISION TIG® 225...

  • Page 65: Active Scr Test

    F-25 TROUBLESHOOTING AND REPAIR Service and repair should be performed by only Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precautions detailed throughout this manual.
  • Page 66 F-26 TROUBLESHOOTING AND REPAIR ACTIVE SCR TEST (continued) FIGURE F.5 – ACTIVE SCR TEST SETUP 6volt Lantern Battery To test SCRs construct the circuit outlined above. Resistor values are plus or minus ten percent. The voltmeter scale should be low, approximately 0-5 or 0-10 volts DC.
  • Page 67 F-27 TROUBLESHOOTING AND REPAIR ACTIVE SCR TEST (continued) SCR1 ANODE SCR1 CATHODE/SCR2 ANODE TEST PROCEDURE (continued) 6. Connect SCR into the test circuit as shown (A) lead to anode (C) lead to cathode and (G) lead to the gate. 7. Close switch SW-1 (switch SW-2 should open), voltmeter should read zero.
  • Page 68 F-28 F-28 NOTES PRECISION TIG® 225...

  • Page 69: Normal Open Circuit Voltage Waveform

    F-29 TROUBLESHOOTING AND REPAIR NORMAL OPEN CIRCUIT VOLTAGE WAVEFORM HIGH VOLTAGE / HIGH FREQUENCY can damage test equipment. • Perform all voltage and waveform checks with high frequency circuit OFF. • Perform High Frequency Disable Procedure. ____________________________________________________________________ AC TIG MODE CAUTION This is the typical AC output voltage waveform generated from a properly...
  • Page 70 F-30 TROUBLESHOOTING AND REPAIR NORMAL OPEN CIRCUIT VOLTAGE WAVEFORM HIGH VOLTAGE / HIGH FREQUENCY can damage test equipment. • Perform all voltage and waveform checks with high frequency circuit OFF. • Perform High Frequency Disable Procedure. ____________________________________________________________________ DC TIG MODE CAUTION This is the typical DC (+) output volt- age waveform generated from a prop-...
  • Page 71 F-31 TROUBLESHOOTING AND REPAIR NORMAL OPEN CIRCUIT VOLTAGE WAVEFORM HIGH VOLTAGE / HIGH FREQUENCY can damage test equipment. • Perform all voltage and waveform checks with high frequency circuit OFF. • Perform High Frequency Disable Procedure. ____________________________________________________________________ AC STICK MODE CAUTION This is the typical AC output voltage waveform generated from a properly...
  • Page 72 F-32 TROUBLESHOOTING AND REPAIR NORMAL OPEN CIRCUIT VOLTAGE WAVEFORM HIGH VOLTAGE / HIGH FREQUENCY can damage test equipment. • Perform all voltage and waveform checks with high frequency circuit OFF. • Perform High Frequency Disable Procedure. ____________________________________________________________________ DC STICK MODE CAUTION This is the typical DC (+) output volt- age waveform generated from a prop-...
  • Page 73 F-33 TROUBLESHOOTING AND REPAIR TYPICAL OUTPUT VOLTAGE WAVEFORM - MACHINE LOADED HIGH VOLTAGE / HIGH FREQUENCY can damage test equipment. • Perform all voltage and waveform checks with high frequency circuit OFF. • Perform High Frequency Disable Procedure. ____________________________________________________________________ MACHINE LOADED TO 180 AMPS AT 16VDC.
  • Page 74 F-34 TROUBLESHOOTING AND REPAIR TYPICAL OUTPUT VOLTAGE WAVEFORM - MACHINE LOADED HIGH VOLTAGE / HIGH FREQUENCY can damage test equipment. • Perform all voltage and waveform checks with high frequency circuit OFF. • Perform High Frequency Disable Procedure. ____________________________________________________________________ MACHINE LOADED TO 180 AMPS AT 16VDC. This is the typical DC (+) output voltage wave- form generated from a properly operating machine.
  • Page 75 F-35 TROUBLESHOOTING AND REPAIR TYPICAL OUTPUT VOLTAGE WAVEFORM HIGH VOLTAGE / HIGH FREQUENCY can damage test equipment. • Perform all voltage and waveform checks with high frequency circuit OFF. • Perform High Frequency Disable Procedure. ____________________________________________________________________ MACHINE LOADED TO 180 AMPS AT 26VDC.
  • Page 76 F-36 TROUBLESHOOTING AND REPAIR TYPICAL OUTPUT VOLTAGE WAVEFORM HIGH VOLTAGE / HIGH FREQUENCY can damage test equipment. • Perform all voltage and waveform checks with high frequency circuit OFF. • Perform High Frequency Disable Procedure. ____________________________________________________________________ MACHINE LOADED TO 180 AMPS AT 26VDC.
  • Page 77 F-37 TROUBLESHOOTING AND REPAIR ABNORMAL OPEN CIRCUIT VOLTAGE - DC TIG MODE ONE OUTPUT SCR NOT FUNCTIONING HIGH VOLTAGE / HIGH FREQUENCY can damage test equipment. • Perform all voltage and waveform checks with high frequency circuit OFF. • Perform High Frequency Disable Procedure. ____________________________________________________________________ CAUTION This is NOT the typical DC (+) output...
  • Page 78 F-38 F-38 NOTES PRECISION TIG® 225...
  • Page 79 TROUBLESHOOTING AND REPAIR REMOVAL AND REPLACEMENT PROCEDURE Service and repair should be performed by only Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precautions detailed throughout this manual.
  • Page 80 F-40 TROUBLESHOOTING AND REPAIR REMOVAL AND REPLACEMENT PROCEDURE (continued) FIGURE F.7 – CASE BACK MOUNTING SCREWS PROCEDURE 1. Remove input power to the TIG 225 machine. 2. Using the 3/8” nutdriver remove the case wrap- around cover. 3. With the slot head screwdriver loosen the input cable strain relief to allow movement of case back.
  • Page 81 F-41 TROUBLESHOOTING AND REPAIR REMOVAL AND REPLACEMENT PROCEDURE (continued) FIGURE F.8 – FRONT PANEL MOUNTING SCREWS FRONT PANEL MOUNTING SCREWS PROCEDURE (continued) 9. Remove plug J2 from the control board. (See Figure F.9.) Also remove plug and lead harness from internal divider panel. 10.
  • Page 82 F-42 F-42 TROUBLESHOOTING AND REPAIR SCR BRIDGE ASSEMBLY REMOVAL AND REPLACEMENT PROCEDURE (continued) FIGURE F.9 – PLUG J2 ON CONTROL BOARD PLUG J2 REMOVED PRECISION TIG 225 CONTROL FIGURE F.10 DIODE PIGTAIL CONNECTION TO POLARITY SWITCH LEAD. DIODE PIGTAIL CONNECTION PRECISION TIG®...
  • Page 83 F-43 TROUBLESHOOTING AND REPAIR REMOVAL AND REPLACEMENT PROCEDURE (continued) 16. With the 3/8” wrench remove the four mount- ing screws holding the SCR bridge assembly to the main transformer frame. Note insulator placement. 17. Carefully remove the SCR bridge assembly from the TIG 225 cutting any necessary cable ties.
  • Page 84 F-44 F-44 NOTES PRECISION TIG® 225...
  • Page 85 TROUBLESHOOTING AND REPAIR REMOVAL AND REPLACEMENT PROCEDURE Service and repair should be performed by only Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precautions detailed throughout this manual.
  • Page 86 F-46 TROUBLESHOOTING AND REPAIR REMOVAL AND REPLACEMENT PROCEDURE (continued) REMOVAL PROCEDURE 1. Remove the input power to the TIG 225 machine. 2. Using the 3/8” nutdriver remove the case wrap- around cover. 3. Using the 3/32” Allen type wrench remove the output control knob.

  • Page 87: Polarity Switch

    F-47 TROUBLESHOOTING AND REPAIR REMOVAL AND REPLACEMENT PROCEDURE (continued) REPLACEMENT PROCEDURE 1. Carefully position the new polarity switch in position on the front panel. Make certain the micro-switch is assembled to the polarity switch correctly. 2. Solder leads #311 and #312 to the micro - switch.
  • Page 88 F-48 F-48 NOTES PRECISION TIG® 225...
  • Page 89 HIGH VOLTAGE TRANSFORMER REMOVAL AND REPLACEMENT PROCEDURE Service and repair should be performed by only Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precautions detailed throughout this manual.
  • Page 90 F-50 TROUBLESHOOTING AND REPAIR HIGH VOLTAGE TRANSFORMER REMOVAL AND REPLACEMENT PROCEDURE (continued) FIGURE F.11 – SECONDARY LEADS AT HIGH FREQUENCY STARTER BOARD REMOVAL PROCEDURE 1. Remove input power to the TIG 225 machine. 2. Using the 3/8” nutdriver remove the case wrap- around cover.
  • Page 91 F-51 TROUBLESHOOTING AND REPAIR HIGH VOLTAGE TRANSFORMER REMOVAL AND REPLACEMENT PROCEDURE (continued) FIGURE F.12 – HIGH VOLTAGE TRANSFORMER MOUNTING INSULATORS FRONT MOUNTING INSULATORS REPLACEMENT PROCEDURE 1. Carefully position the new high voltage trans- former in place in the two rear mounting insula- tors.
  • Page 92 F-52 F-52 NOTES PRECISION TIG® 225...
  • Page 93 MAIN TRANSFORMER AND OUTPUT CHOKE ASSEMBLY REMOVAL AND REPLACEMENT PROCEDURE Service and repair should be performed by only Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precautions detailed throughout this manual.
  • Page 94 F-54 TROUBLESHOOTING AND REPAIR MAIN TRANSFORMER AND OUTPUT CHOKE ASSEMBLY REMOVAL AND REPLACEMENT PROCEDURE (continued) REMOVAL PROCEDURE 1. Remove input power to the TIG 225 machine. 2. Perform the SCR Bridge Assembly Removal Procedure. 3. Unsolder the two 115VAC leads and leads B231 and B232 from the main transformer leads.

  • Page 95: Retest After Repair

    F-55 Should a machine under test be rejected for any reason requiring the removal of any mechanical part that could affect the machine’s electrical characteristics, or if any electrical components are repaired or replaced, the machine must be retested. Input Volts/Hertz 208/60 230/60 Stick Mode OCV...
  • Page 96 F-56 F-56 NOTES PRECISION TIG® 225...
  • Page 97 TABLE OF CONTENTS - DIAGRAM SECTION Electrical Diagrams ..............G-1 Wiring Diagram (G5646) .
  • Page 98 (L2) (L1) POWER SWITCH 10K A-B AT MINIMUM OPTIONAL REMOTE REMOTE RECEPTACLE AMPTROL POLARITY SWITCH MICRO SWITCH A-C, D-E, B-F OPEN FRONT B-D, C-E, A-F, G-H CLOSED GANG B-D, A-E, C-F, G-H CLOSED REAR GANG MICRO-SWITCH 312A 311A POLARITY (REAR VIEW, SWITCH SHOWN IN AC POSITION) WORK...
  • Page 99 CHANGEDETAIL: RELEASEDFROM XA.02 ENGINEERING CONTROLLED MANUFACTURER: G5647 DISPLAY PRESET AT IDLE +15V +24V ACTUAL AMP WHEN WELDING NO HOLD FUNCTION 3 DIGIT FIRE_SCR METER GATING & SNUBBER (DISP1) OUTPUT CONTROL & MODE SETTINGS ARE MEMORIZED AT POW ER +15V - DOW N AND RECALLED PHASE METER ATPOWER - UP...
  • Page 100 This diagram is for reference only. It may not be accurate for all machines covered by this manual.
  • Page 101 This diagram is for reference only. It may not be accurate for all machines covered by this manual.
  • Page 102 This diagram is for reference only. It may not be accurate for all machines covered by this manual.
  • Page 103 Lincoln Electric discourages board level troubleshooting and repair since it may compromise the quality of the design and may result in danger to the Machine Operator or Technician.
  • Page 104 Lincoln Electric discourages board level troubleshooting and repair since it may compromise the quality of the design and may result in danger to the Machine Operator or Technician.
  • Page 105 ENGINEERING CONTROLLED S22530-1B0 MANUFACTURER: ARC STABILIZER CAPACITOR CONNECTION MADE THROUGH HOLE WITH SOLDER PAD Graphic 600V 600V 600V 600V GND CONNECTION MADE THROUGH SOLDER PAD AND SCREW TO STEEL STANDOFF ON MACHINE THIS DOCUMENT CONTAINS PROPRIETARY INFORMATION OWNED BY LINCOLN GLOBAL, INC. AND MAY NOT BE DUPLICATED, COMMUNICATED TO OTHER PARTIES OR USED FOR ANY PURPOSE WITHOUT THE EXPRESS WRITTEN PERMISSION OF LINCOLN GLOBAL, INC.
  • Page 106 Lincoln Electric discourages board level troubleshooting and repair since it may compromise the quality of the design and may result in danger to the Machine Operator or Technician.

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