Thermal Arc 251 FABRICATOR Service Manual
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Thermal Arc 251 FABRICATOR Service Manual

Mig welding machine
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251

Service Manual

FABRICATOR
MIG WELDING MACHINE
Revision No: AG
Operating Features:
®
Issue Date: June 15, 2006
208
208
230
230
V V
V V
Manual No.: 0-4786B
60 60
H
Z

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  • Page 1: Service Manual

    ® FABRICATOR MIG WELDING MACHINE Service Manual Revision No: AG Issue Date: June 15, 2006 Manual No.: 0-4786B Operating Features: 60 60...
  • Page 3 WARNINGS Read and understand this entire Manual and your employer’s safety practices before installing, operating, or servicing the equipment. While the information contained in this Manual represents the Manufacturer's best judgement, the Manufacturer assumes no liability for its use. Fabricator 251 MIG Welding Machine Service Manual Number 0-4786B for: Package System Part Number 100048D-002 Power Source Part Number 707237...

  • Page 4: Table Of Contents

    TABLE OF CONTENTS SECTION 1: SAFETY INSTRUCTIONS AND WARNINGS ............1-1 1.01 Arc Welding Hazards ..................1-1 1.02 Principal Safety Standards ................1-4 1.03 Precautions De Securite En Soudage A L’arc ..........1-5 1.04 Dangers relatifs au soudage à l’arc ..............1-5 1.05 Principales Normes De Securite ..............
  • Page 5 TABLE OF CONTENTS (continued) TABLE OF CONTENTS SECTION 4: OPERATION ................... 4-1 4.01 Power Supply Controls, Indicators and Features ..........4-1 4.02 Weld Mode Selector ..................4-6 4.03 TWECO Weldskill 300 AMP Weld Gun ............4-8 4.04 Installing A New Wire Conduit ................ 4-8 4.05 MIG Gun Maintenance ..................
  • Page 6 TABLE OF CONTENTS SECTION 8: CIRCUIT OPERATION ................8-1 8.01 Circuit Operation Of The Control PCB 7977964 ..........8-1 8.02 Circuit Operation Of The MIG Timer PCB 7977965 ......... 8-2 8.03 Circuit Operation Of The Digital Volt/Amp PCB 704883 ........8-2 8.04 Circuit Operation Of The Spool Gun PCB 7978034 .........

  • Page 7: Section

    FABRICATOR 251 SECTION 1: SAFETY INSTRUCTIONS AND WARNINGS WARNING PROTECT YOURSELF AND OTHERS FROM POSSIBLE SERIOUS INJURY OR DEATH. KEEP CHILDREN AWAY. PACEMAKER WEARERS KEEP AWAY UNTIL CONSULTING YOUR DOCTOR. DO NOT LOSE THESE INSTRUCTIONS. READ OPERATING/INSTRUCTION MANUAL BEFORE INSTALLING, OPERATING OR SERVICING THIS EQUIPMENT. Welding products and welding processes can cause serious injury or death, or damage to other equipment or property, if the operator does not strictly observe all safety rules and take precautionary actions.
  • Page 8 FABRICATOR 251 3. Use protective screens or barriers to protect others from flash and glare; warn others not to watch the arc. WARNING 4. Wear protective clothing made from durable, flame-resistant material (wool and leather) and foot protection. WELDING can cause fire or explosion. 5.
  • Page 9 FABRICATOR 251 2. If used in a closed area, vent engine exhaust outside and away from any building air intakes. WARNING WARNING FLYING SPARKS AND HOT METAL can cause injury. Chipping and grinding cause flying metal. As welds cool, they can throw off slag. ENGINE FUEL can cause fire or explosion.

  • Page 10: Principal Safety Standards

    FABRICATOR 251 1.02 Principal Safety Standards Safety in Welding and Cutting, ANSI Standard Z49.1, from American WARNING Welding Society, 550 N.W. LeJeune Rd., Miami, FL 33126. Safety and Health Standards, OSHA 29 CFR 1910, from Superintendent STEAM AND PRESSURIZED HOT COOLANT can burn of Documents, U.S.

  • Page 11: Precautions De Securite En Soudage A L'arc

    FABRICATOR 251 1.03 Precautions De Securite En Soudage A L’arc MISE EN GARDE LE SOUDAGE A L’ARC EST DANGEREUX PROTEGEZ-VOUS, AINSI QUE LES AUTRES, CONTRE LES BLESSURES GRAVES POSSIBLES OU LA MORT. NE LAISSEZ PAS LES ENFANTS S’APPROCHER, NI LES PORTEURS DE STIMULATEUR CARDIAQUE (A MOINS QU’ILS N’AIENT CONSULTE UN MEDECIN). CONSERVEZ CES INSTRUCTIONS.
  • Page 12 FABRICATOR 251 AVERTISSEMENT AVERTISSEMENT LES VAPEURS ET LES FUMEES SONT DANGEREUSES LE RAYONNEMENT DE L’ARC PEUT BRÛLER LES YEUX POUR LA SANTE. ET LA PEAU; LE BRUIT PEUT ENDOMMAGER L’OUIE. Le soudage dégage des vapeurs et des fumées L’arc de soudage produit une chaleur et des rayons dangereuses à...
  • Page 13 FABRICATOR 251 7. Ne soudez des tôles galvanisées ou plaquées au plomb ou au cadmium que si les zones à souder ont été grattées à fond, que si AVERTISSEMENT l’espace est bien ventilé; si nécessaire portez un respirateur à ad- duction d’air.

  • Page 14: Principales Normes De Securite

    FABRICATOR 251 Les accumulateurs contiennent de l’électrolyte acide et 1. Utilisez l’équipement à l’extérieur dans des aires ouvertes et bien ventilées. dégagent des vapeurs explosives. 2. Si vous utilisez ces équipements dans un endroit confiné, les 1. Portez toujours un écran facial en travaillant sur un accumu-lateur. fumées d’échappement doivent être envoyées à...

  • Page 15: Introduction

    Include the Service Manual number and equipment identification numbers. Electronic copies of this manual can also be downloaded at no charge in Acrobat PDF format by going to the Thermal Arc web site listed below and clicking on the Literature link: http://www.thermalarc.com June 15, 2006...

  • Page 16: Symbol Chart

    FABRICATOR 251 2.04 Symbol Chart Note that only some of these symbols will appear on your model. Wire Feed Function Single Phase Wire Feed Towards Workpiece With Three Phase Output Voltage Off. Three Phase Static Frequency Converter- Welding Gun Dangerous Voltage Transformer-Rectifier Purging Of Gas Increase/Decrease...

  • Page 17: General Information

    • Never watch the welding arc with naked eyes. Al- from standard specification without prior written approval ways use and wear a welding mask fitted with the of Thermal Arc. The purchaser of this equipment shall correct filter lens. have the sole responsibility for any malfunction which •...

  • Page 18: Duty Cycle

    FABRICATOR 251 2.09 Duty Cycle The rated duty cycle of a welding Power Supply is the operating time it may be used at its rated output current without exceeding the temperature limits of the insulation of the component parts. To explain the ten minute duty cycle period the following example is used.
  • Page 19 FABRICATOR 251 Fabricator 251 Package System Part Number 100048D-002 Power Source Part Number 707237 Power Source Weight 227lb (103kg) 32” x 27-3/16” x 36-3/4” Power Source Dimensions HxWxD (813 x 691 x 933mm) (including wheels and cylinder carrier) Nominal Input Voltage 208V 230V Number of Phases...

  • Page 20: Included Items For Fabricator 251

    FABRICATOR 251 2.11 Included Items for Fabricator 251 Fabricator 251 Package System Contents Factory Fitted Wheeling Kit Factory Fitted Dual Cylinder Rack Factory Fitted Primary Power Cable 8AWG, 10ft (3m) with Plug NEMA 6-50P Work Lead 10ft (3m) Cable Stowage Hooks Regulator/Flow Meter –...

  • Page 21: Installation

    FABRICATOR 251 3.02 Location SECTION 3: INSTALLATION Be sure to locate the Power Supply according to the following guidelines: In areas, free from moisture and dust. 3.01 Environment In areas, free from oil, steam and corrosive gases. The Fabricator 251 is NOT designed for use in In areas, not subjected to abnormal vibration or shock.

  • Page 22: Primary Power Requirements

    Install a power outlet for each Power Supply and fit fuses as per the machine specifications. WARNING Thermal Arc advises that your Fabricator 251 be electrically connected by a qualified electrical trades- person. The Fabricator 251 Power Supply is factory connected for the following input power supply voltage:...
  • Page 23 FABRICATOR 251 Changing the Voltage Selection 1. Disconnect the power supply from the input power source. 2. Refer to Figure 3-1. The power supply comes wired for 230V. Locate the two blue input power wires where they are secured to the input voltage selection block. Loosen the set screw for both voltage locations. 3.

  • Page 24: Quick Setup

    FABRICATOR 251 7. Fit the electrode wire spool to the wire reel hub 3.06 Quick Setup located behind the electrode wire compartment door. CAUTION 8. Fit the TWECO Weldskill MIG gun and trigger wires through/to the front of the unit. To obtain adequate air flow and cooling for 9.
  • Page 25 FABRICATOR 251 Shielding Regulator and Flow Meter “Cracking” Shielding Shielding Shielding Art # A-07278 Stowage Hook Gas Hose Figure 3-2 Gas Cylinder Installation June 15, 2006...
  • Page 26 FABRICATOR 251 Adjusting Regulator Adjust control knob of regulator to the required flow rate, indicated on gauge dial. (Refer to Figure 3-3) The gas flow rate should be adequate to cover the weld zone to stop weld porosity. Excessive gas flow rates may cause turbulence and weld porosity.

  • Page 27: Attaching The Gun And Cable Assembly To The Power Source

    Lubricate the O-ring on the quick-connect fitting of the gun cable with grease (Dow company #4 com- pound or equivalent, or Thermal Arc #903910) 2. Route the gun cable through the access hole in the front panel. Refer to Figures 3-5 and -3-6.
  • Page 28 FABRICATOR 251 Front Panel Access Hole Art # 0-7148 Trigger Receptacle Figure 3-5: Route Gun Cable Through Front Panel Access Hole and Connect Trigger Loosen Thumbscrew Art # A-07149 Tighten Thumbscrew Figure 3-6: Mount Gun Cable to Adapter Socket June 15, 2006...

  • Page 29: Input And Output Wire Guide Installation

    FABRICATOR 251 3.09 Input And Output Wire Guide To ensure proper wire feed, the groove closest to the motor must match the electrode wire size being used. Installation Refer to Figure 3-7. .045” (1.2mm) Stamping Install the input wire guide (the longer one) by loosening .045 the input guide lockscrew and inserting the guide into the hole in the feedhead assembly.

  • Page 30: Installing Wire Spool

    FABRICATOR 251 3.11 Installing Wire Spool As delivered from the factory, the unit is set for a 33/44 lb. or 12" (300mm) spool. Installation of wire spool 1. Remove Wire Spool Hub Nut by turning counter clock wise (to the left). 2.

  • Page 31: Inserting Wire Into The Feedhead

    FABRICATOR 251 3.12 Inserting Wire into the Feedhead WARNING ELECTRIC SHOCK CAN KILL! Make certain the input power is disconnected from the power supply before proceeding. Do not reattach the input power until told to do so in these instructions. 1.

  • Page 32: Wirefeeder Feed Roll Pressure Adjustment

    FABRICATOR 251 Wheel Brake Hex Head Bolt Pressure Adjustment Device Art # A-07162 Spool Hub Nut Figure 3-12: Wire Installed 3.13 Wirefeeder Feed Roll Pressure Adjustment The idler roll on the swing arm applies pressure to the grooved drive roll via an adjustable tension devise. The Pressure Adjustment Device should be set to a minimum pressure that will provide satisfactory wire feed without slippage.

  • Page 33: Spool Gun Attachment

    FABRICATOR 251 3.15 Spool Gun Attachment A spool gun can readily be used with the Fabricator 251 power supply. 1. Attach appropriate input gas to the Spool Gun input gas connection on the rear of the unit. (Refer to Figure. 3- 2.

  • Page 34: Polarity Changeover

    FABRICATOR 251 3.16 Polarity Changeover WARNING ELECTRIC SHOCK CAN KILL! Make certain the input power is disconnected from the power supply before proceeding. Do not reattach the input power until told to do so in these instructions. The output terminals are located on the front panel of the welding power source. CABLE TO GUN, CABLE TO WORK CABLE CONNECTIONS PROCESS...
  • Page 35 FABRICATOR 251 Work Lead Connected for D.C. Electrode Negative (DCEN) Welding Art # A-07164 Figure 3-15: Polarity Connections for DCEN Changing polarity process. a. Locate the two terminal knobs at the front of the machine. Refer to Figures 3-14 and 3-15. b.
  • Page 36 FABRICATOR 251 NOTES: 3-16 June 15, 2006...

  • Page 37: Operation

    FABRICATOR 251 SECTION 4: OPERATION WARNING DO NOT TOUCH the electrode wire while it is being fed through the system. The electrode wire will be at welding voltage potential. 4.01 Power Supply Controls, Indicators and Features Thermal Overload Indicator Digital Display Wire Feed Speed Control Voltage / Amp Selection Button...
  • Page 38 FABRICATOR 251 On / Standby Power Switch The indicator light is provided to indicate when the Fabricator 251 is connected to the Primary Input Power Supply Voltage. With the On/Off Switch in the Off position, the auxiliary power and the fan are turned off and the switch is illumi- nated.
  • Page 39 FABRICATOR 251 The Digital Meter will hold the last reading at completion of welding for 10 seconds to allow for easy operator set Digital AMP Reading to IPM Conversion STEEL Current (Amps) Art # A-07451 Figure 4-3: Steel - AMP to IPM Conversion STAINLESS STEEL Current (Amps) Art # A-07452...
  • Page 40 FABRICATOR 251 ALUMINUM Current (Amps) Art # A-07453 Figure 4-5: Aluminum - AMP to IPM Conversion Thermal Overload The critical components for thermal protection are the rectifier stack and the transformer, which are fitted with thermal overload cut out devices. If the overload is activated then the machine should be left to cool for approxi- mately 15 minutes before resuming welding.
  • Page 41 FABRICATOR 251 Positive and Negative Welding Current Terminals Spool Gun Interface Amphenol Connector Refer back to Figure 4-1. Both terminals located at The Spool Gun Interface 10 pin connector is used to the bottom of the unit are shown without the terminal connect a spool gun to the Fabricator 251 (refer to knob.

  • Page 42: Weld Mode Selector

    FABRICATOR 251 4.02 Weld Mode Selector The Weld Mode Selector switch selects the method of welding mode. WELD WELD DWELL DWELL WELD MODE WELD MODE (STITCH) (STITCH) (SPOT / STITCH) (SPOT / STITCH) STITCH STITCH SPOT SPOT 4T 4T 2T 2T BURNBACK BURNBACK Art # A-07183...
  • Page 43 FABRICATOR 251 STITCH: DWELL STITCH TIMER CONTROL This mode of welding is used to weld two or more DWELL (STITCH) CONTROL KNOB components together with a stitch weld. The WELD When the Weld Mode control is in the Stitch position, the (Spot/Stitch) shaft controls the welding or ‘ON’...

  • Page 44: Tweco Weldskill 300 Amp Weld Gun

    TWECO Weldskill MIG guns may be fitted to many different types of MIG welding Power Supplies so that your whole shop can be converted to TWECO Weldskill. Not only will this give greater reliability (and hence greater productivity) but it will reduce stockholding of consumable parts. See your Thermal Arc distributor for details. Gun Consumable Parts See Appendix at the back of this manual.
  • Page 45 FABRICATOR 251 2. To install a new conduit, first inspect the o-ring gas seal on the conduit for cuts or damage. Start from the connector plug end of the assembly and begin pushing the conduit through the connector plug, cable assem- bly and into the gun.

  • Page 46: Mig Gun Maintenance

    FABRICATOR 251 4.05 MIG Gun Maintenance Remove dust and metallic particles from the gun conduit by forcing clean, dry compressed air into the conduit once a week. This will minimize wire feeding problems. 4.06 Basic Welding Technique Setting of the Power Supply The setting of the Fabricator 251 requires some practice by the operator, the welding Power Supply having two control settings that have to balance.
  • Page 47 FABRICATOR 251 Distance from the MIG Gun Nozzle to the Work Piece The electrode stick out from the MIG gun nozzle should be between 5/64" (2.0mm) to 13/64" (5.0mm). This distance may vary depending on the type of joint that is being welded. Solid Wire Flux Cored Wire Art # A-07186...

  • Page 48: Stitch Welding Operation

    FABRICATOR 251 Advantages of MIG welding forehand: - Allows superior visibility of the weld zone - Flatter weld bead - Shallower penetration Vertical Forehand Backhand Art # A-07185 Figure 4-17: MIG Gun Angle 4.07 Stitch Welding Operation Welding consumable costs can be reduced by replacing a continuous weld bead with the Stitch weld bead. It will also reduce heat distortion in thin plate.

  • Page 49: Spot Welding Operation

    FABRICATOR 251 4.08 Spot Welding Operation Fit an optional spot welding nozzle to the MIG gun for consistent spot welding operations. Refer to the spot welding nozzle table below. The Fabricator 251 will operate effectively using .030” (0.8mm) electrode wire when spot welding.

  • Page 50: Gas Selection For Gas Metal Arc Welding

    FABRICATOR 251 4.09 Gas Selection for Gas Metal Arc Welding Suggested Base Plate Filler Transfer Welding Metal Type Shielding Comments Thickness Metal Mode Positions Greater than 22 ER70S-X Short High welding speeds. Good Carbon 100% CO gauge (.030”) Circuit Position penetration and pool control.
  • Page 51 FABRICATOR 251 THIS PAGE HAS BEEN LEFT INTENTIONALLY BLANK June 15, 2006 4-15...

  • Page 52: Welding Setting Selection Guide

    FABRICATOR 251 4.10 Welding Setting Selection Guide Shielding Gas Wire Size Material Type Wire Type (Diameter) and Flow Rate .035” (0.9mm) 100% CO 25cfh .045” (1.2mm) .023” (0.6mm) .030” (0.8mm) 75% Ar 25% ,25cfh Solid .035” (0.9mm) (or hard) Steel .045”...
  • Page 53 FABRICATOR 251 Coarse Voltage THICKNESS Fine Voltage Step Wire Coarse Fine Speed Voltage Voltage 22 ga. (0.8mm) 18 ga. (1.2mm) 16 ga. (1.6mm) 1/8” (3.2mm) 1/4” (6.4mm) 3/8” (9.5mm) 1/2” (12.7mm) 5/8” (15.9mm) 7.25 1.75 4.25 2.25 5.25 8.25 3.25 5.75 6.75 5.75...
  • Page 54 FABRICATOR 251 NOTES 4-18 June 15, 2006...

  • Page 55: Maintenance & Troubleshooting

    FABRICATOR 251 SECTION 5: MAINTENANCE & TROUBLESHOOTING 5.01 Routine Maintenance & Inspection The only routine maintenance required for the Fabricator 251 is a thorough cleaning and inspection, with the frequency depending on the usage and the operating environment. WARNING Disconnect the Fabricator from the Input power supply voltage before disassembling. Special maintenance is not necessary for the control unit parts in the Power Supply.
  • Page 56 FABRICATOR 251 Maintain more often Warning! if used under severe Disconnect input power before maintaining. conditions Each Use Visual check of torch Visual check of Consumable parts regulator and pressure Weekly Visually inspect the torch Visually inspect the body and consumables cables and leads.

  • Page 57: Troubleshooting

    The basic level of troubleshooting is that which can be performed without special equipment or knowledge, and without removing the covers from the Power Supply. If major components are faulty, then the Power Supply should be returned to an Accredited Thermal Arc Service Agent for repair.

  • Page 58: Solving Problems Beyond The Welding Terminals

    FABRICATOR 251 6.02 Solving Problems Beyond the Welding Terminals The general approach to fix GMAW/FCAW problems is to start at the wire spool then work through to the MIG torch. There are two main areas where problems occur: Porosity When there is a gas problem the result is usually porosity within the weld metal. Porosity always stems from some contaminant within the molten weld pool which is in the process of escaping during solidification of the molten metal.
  • Page 59 FABRICATOR 251 2. Inconsistent wire feed FAULT CAUSE REMEDY 1. Wire spool brake is a. Feed roll driven by motor in the cabinet will slip. too tight. 2. Wire spool brake is a. Wire spool can unwind and tangle too loose. a.

  • Page 60: Welding Problems

    FABRICATOR 251 6.03 Welding Problems FAULT CAUSE REMEDY 1. Welding arc voltage a. Reduce voltage by reducing the voltage too high. selection switch position or increase the wire feed speed. A. Undercut 2. Incorrect torch a. Adjust angle angle 3. Excessive heat a.
  • Page 61 6. Weld speed too fast a. Reduce weld speed. 1. Faulty rectifier unit a. Have an Accredited THERMAL ARC Service Agent to test then replace the faulty component. B. Cold weld puddle 2. Loose welding cable a.

  • Page 62: Power Supply Problems

    B. Primary power supply voltage 1. Primary fuse is blown. a. Replace primary fuse. is ON. Indicator light is not lit 2. Broken connection in a. Have an Accredited Thermal Arc and welding arc can not be primary circuit. Service Agent check primary established.

  • Page 63: Advanced Troubleshooting

    FABRICATOR 251 SECTION 7: ADVANCED TROUBLESHOOTING If the problem cannot be solved by the basic (external) trouble shooting guide, the Power Source covers and/or the Wire Feeder covers will have to be removed. The advanced level of troubleshooting allows the technician with a few common tools to remove the covers and analyze failures.

  • Page 64: Initial Setup Conditions

    FABRICATOR 251 7.02 Initial Setup Conditions 7.03 Primary Power Test Set the power supply controls and connect cables as A. Close primary disconnect device and observe the follows: following: 1. ON/OFF Switch to OFF Position 1. Green Indictor Lamp inside ON/OFF Switch illuminates 2.

  • Page 65: Logic And Control Tests

    FABRICATOR 251 7.04 Logic and Control Tests G. Release Gun Switch 1. Feed Roll stops immediately A. Depress Gun Switch and observe the following: 2. Display reads "15.0 V" 1. Gas flows 2. After 1 ½ seconds 2. Contactor energizes a.

  • Page 66: Spool Gun Control (J1) Test

    FABRICATOR 251 J. Set MODE SELECTOR SWITCH to STITCH position. O. Set WIRE SPEED CONTROL to "4" Set WELD (SPOT/STITCH) TIMER CONTROL to P. Set COARSE VOLTAGE SELECTOR SWITCH to minimum. position "L". 1. Depress Gun Switch Q. Set FINE VOLTAGE SELECTOR SWITCH to position "1". a.

  • Page 67: Output Voltage Test

    FABRICATOR 251 7.06 Output Voltage Test A. Set COARSE VOLTAGE SELECTOR SWITCH to position "L" B. Set FINE VOLTAGE SELECTOR SWITCH to position "1" C. Connect voltmeter probes to + & - WELDING TERMINALS D. Depress Gun Switch and observe voltage E.

  • Page 68: Wire Feed & Weld Test

    FABRICATOR 251 7.07 Wire Feed & Weld Test 7.08 Primary Power Problems A. Close the PRESSURE ADJUST DEVICE. Connect the GUN A. Green Indicator in ON/OFF Switch is not POLARITY LEAD to the POSITIVE WELDING TERMINAL illuminated and fan does turn when ON/OFF (+).

  • Page 69: Logic And Control Problems

    FABRICATOR 251 8. Faulty MAIN PCB 1 7.09 Logic and Control Problems a. Measure between JB-4 to JB-11 at PCB 1 for A. Nothing happens when gun switch is depressed; approx 30 VAC when gun switch is closed. If No gas flow, contactor does not energize, feed voltage is not present, replace PCB.

  • Page 70: Spool Gun Control (J1) Problem

    FABRICATOR 251 3. Open wire from Rectifier assembly to Control PCB. 7.10 Spool Gun Control (J1) Problem a. With gun switch closed, measure for approx A. Gas does not flow when jumper is connected 15 VDC at Control PCB between JB7 (-) to JB9 between J11 Pins D &...

  • Page 71: Wire Feed And Weld Problems

    FABRICATOR 251 7.12 Wire Feed and Weld Problems A. Poor or inconsistent arc transfer or no arc transfer 1. Poor work cable connection or open work cable a. Clean contact point, check continuity of cable and cable to clamp connection. Replace if work cable if required.

  • Page 72: Sw3 Coarse And Sw4 Fine Rotary Switch Test

    FABRICATOR 251 7.14 SW3 Coarse and SW4 Fine Rotary Switch Test WIRE No'S. TERMINAL No'S. TOP OF SWITCH TERMINAL No'S. WIRE No'S. WIRE No'S. TERMINAL No'S. BOTTOM OF SWITCH TERMINAL No'S. WIRE No'S. Figure7-2: 3-Position Rotary Switch, Coarse WIRE No'S. TERMINAL No'S.
  • Page 73 FABRICATOR 251 VOLTAGE CONTROL SWITCH TEST One at a time remove SW-3 and SW-4 from front panel, disconnect wires, reconnect to panel and check continuity of switch per figure 7-5. Set Screw Knob Retainer Locking Collar Rotary Switch (SW4 Fine) Figure 7-4: Rotary Switch SW3 and SW4 Removal SWITCH 2 COARSE SWITCH 3 FI NE...

  • Page 74: Mig Timer Pcb (Pcb2) Test

    FABRICATOR 251 7.15 MIG Timer PCB (PCB2) Test Using the MAIN PCB terminal JB-5 as common measure the voltage at JD-1. This should measure 20VDC when the Gun Switch is closed. Then measure the voltage at JD-2. WELD MODE SELECTOR WITCH VOLTAGE AT JD-2 POSITION 10VDC when Gun Switch closed.

  • Page 75: Rectifier Assembly Test

    FABRICATOR 251 7.16 Rectifier Assembly Test 1. Disconnect one of the Main Transformer connections from the rectifier assembly. 2. Disconnect and isolate wires from the Negative output of the Rectifier Assembly See Figure 7-3. 3. Disconnect JB connector from MAIN PCB 1. 4.

  • Page 76: Main Transformer Test

    FABRICATOR 251 7.17 Main Transformer Test Disconnect the secondary of the Main Transformer T2 from the rectifier bridge and measure output voltage between the two transformer output connections as follows: COARSE VOLTAGE SELECTION FINE VOLTAGE SELECTOR VOLTAGE AC (approx.) SWITCH SETTING SWITCH SETTING 11.8 12.2...

  • Page 77: Circuit Operation

    FABRICATOR 251 SECTION 8: CIRCUIT OPERATION 8.01 Circuit Operation Of The Control PCB 7977964 Power Supply 24VAC is taken from the auxiliary wiring of the fan. This voltage is then connected to the PCB 7977964 where it is half wave rectified and filtered. This voltage is then fed to a zener regulator to provide the +15VDC supply for the electronics on the circuit board Inputs to the Control PCB CONNECTOR JA...

  • Page 78: Circuit Operation Of The Digital Volt/Amp Pcb 704883

    FABRICATOR 251 CONNECTOR JB 8.02 Circuit Operation Of The MIG Timer PCB 7977965 Terminal JB-1 wiper of wire speed control potentiometer, This board is connected by way of a 6-way cable and varies between <2V to approximately 4.7VDC does not have any terminals available to measure. (pot wiper) reference JA-5 or JB-5...

  • Page 79: Circuit Operation Of The Spool Gun Pcb 7978034

    FABRICATOR 251 8.04 Circuit Operation Of The Spool Gun Terminal X2/4 trigger relay - connects to trigger input of PCB 7978034 7977964 PCB CONNECTOR X1 Terminal X2/5 trigger relay - connects to trigger input of Terminal X1/1 7977964 PCB motor relay "normally open" - connects to spool gun motor Terminal X2/6...
  • Page 80 FABRICATOR 251 June 15, 2006...

  • Page 81: Parts List

    FABRICATOR 251 SECTION 9: PARTS LIST 9.01 Equipment Identification All identification numbers as described in the Introduction chapter must be furnished when ordering parts or making inquiries. This information is usually found on the nameplate attached to the equipment. Be sure to include any dash numbers following the Part or Assembly numbers.

  • Page 82: External Replacement Parts

    FABRICATOR 251 9.03 External Replacement Parts ITEM ITEM ITEM ITEM ITEM P P P P P AR ART NUMBER T NUMBER T NUMBER T NUMBER T NUMBER DESCRIPTION DESCRIPTION DESCRIPTION DESCRIPTION DESCRIPTION REF DESIGNA REF DESIGNA REF DESIGNA REF DESIGNA REF DESIGNATION TION TION...
  • Page 83 FABRICATOR 251 4, 23 Art # A-07513 24, 25 June 15, 2006...

  • Page 84: Internal Replacement Parts (1)

    FABRICATOR 251 9.04 Internal Replacement Parts (1) ITEM ITEM ITEM ITEM ITEM P P P P P AR ART NUMBER T NUMBER T NUMBER T NUMBER T NUMBER DESCRIPTION DESCRIPTION DESCRIPTION DESCRIPTION DESCRIPTION REF DESIGNA REF DESIGNA REF DESIGNA REF DESIGNA REF DESIGNATION TION TION...
  • Page 85 FABRICATOR 251 Art # A-07516 June 15, 2006...

  • Page 86: Major Electrical And Mechanical Replacement Parts

    FABRICATOR 251 9.05 Major Electrical and Mechanical Replacement Parts ITEM ITEM ITEM ITEM ITEM P P P P P AR ART NUMBER T NUMBER T NUMBER T NUMBER T NUMBER DESCRIPTION DESCRIPTION DESCRIPTION DESCRIPTION DESCRIPTION REF DESIGNA REF DESIGNA REF DESIGNA REF DESIGNA REF DESIGNATION TION...

  • Page 87: Internal Replacement Parts (2)

    FABRICATOR 251 9.06 Internal Replacement Parts (2) ITEM ITEM ITEM ITEM ITEM P P P P P AR ART NUMBER T NUMBER T NUMBER T NUMBER T NUMBER DESCRIPTION DESCRIPTION DESCRIPTION DESCRIPTION DESCRIPTION REF DESIGNA REF DESIGNA REF DESIGNA REF DESIGNA REF DESIGNATION TION TION...

  • Page 88: Internal Replacement Parts-Spool Assembly

    FABRICATOR 251 9.07 Internal Replacement Parts-Spool Assembly ITEM ITEM ITEM ITEM ITEM P P P P P AR ART NUMBER T NUMBER T NUMBER T NUMBER T NUMBER DESCRIPTION DESCRIPTION DESCRIPTION DESCRIPTION DESCRIPTION See Note Screw, Hex HD, 3/8"-16x3/4",STZP 170459-001 Plunger, Spring, Nut Hub 405377 Nut, Wire Spool Hub...

  • Page 89: Internal Replacement Parts-Wire Feeder

    FABRICATOR 251 9.08 Internal Replacement Parts-Wire Feeder ITEM ITEM ITEM ITEM ITEM P P P P P AR ART NUMBER T NUMBER T NUMBER T NUMBER T NUMBER DESCRIPTION DESCRIPTION DESCRIPTION DESCRIPTION DESCRIPTION Feed rolls and guides may be found in the Feed Roll kit located in the Appendix section of this manual. 870387PKD Gear, Idle Roll, 2R Plate 871010PKD...

  • Page 90: Wire Feeder Replacement Parts

    FABRICATOR 251 9.09 Wire Feeder Replacement Parts Item Item Item Qty Item Item Qty Ref Ref. Des. . Des. . Des. . Des. . Des. Description Description Description Description Description Part Number Part Number Part Number Part Number Part Number Rod, Tension Subassembly, WF 870933PKD Pressure Arm, 2R M/C, WF...

  • Page 91: Appendix 1: Optional Accessories And Consumables

    FABRICATOR 251 APPENDIX 1: OPTIONAL ACCESSORIES AND CONSUMABLES For Tweco/Victor Inquiries and Orders: Call 1-800-318-6819 Consumable Parts Management Group GUNS Tweco® WeldSkill 15ft 43340 Gun assembly with 15ft cable (supplied with package), 300 Amp @ 30% Tweco® No. 4 12ft 412-3545 Gun assembly with 12ft cable, 400 Amp @ 60% Tweco®...

  • Page 92: Appendix 2: Power Supply Circuit Diagram

    FABRICATOR 251 APPENDIX 2: POWER SUPPLY CIRCUIT DIAGRAM • Note the model number shown on the equipment nameplate 4 BLUE COARSE 4A BLUE 8&8A BRN FABRICATOR 251 (10) 8 BRN 9&9A BLK (12) (11) 9 BLK 10&10A RED Input Ter minal Block 1 RED K1\3 (8) (7)
  • Page 93 FABRICATOR 251 SWITCH 2 COARSE SWITCH 3 FI NE SWI TCH POSITI ON POSITI ON 10 12 10 12 Bridge Recti fier POSITIVE OUTPUT Induct or TERMINAL PLUGSOCKET 21 ORN X1/6 PCB 4 22 VIO Varis tor X1/5 + C1-C4 23 GRY X1/4 704883...

  • Page 94: Appendix 3: Main Pcb Circuit Diagram

    FABRICATOR 251 APPENDIX 3: MAIN PCB CIRCUIT DIAGRAM 30 VAC Art # A-07520 June 15, 2006...
  • Page 95 FABRICATOR 251 82 BENNING SREET WEST LEBANON, NH 03784, USA DESCRIPTION: FABRICATOR MAIN PCB 7977964 Art # A-07520 June 15, 2006...

  • Page 96: Appendix 4: Spot Timer Circuit Diagram

    FABRICATOR 251 APPENDIX 4: SPOT TIMER CIRCUIT DIAGRAM Art # A-07521 June 15, 2006...
  • Page 97 FABRICATOR 251 82 BENNING SREET WEST LEBANON, NH 03784, USA DESCRIPTION: FABRICATOR SPOT TIMER 7977965 CODE DESIGN: Art # A-07521 June 15, 2006...
  • Page 98 FABRICATOR 251 APPENDIX 5: SPOOL GUN PCB +14Vdc +35Vdc +14Vdc 1N4004 100n +Vout 1N4004 1N4004 LM317T 270R 22u 50V 100n 100n 470u 50V 4013 1N4004 1N4004 +14Vdc +14Vdc +14Vdc 100K 100n 1N4004 LM324 100n LM324 1N4004 +14Vdc 24VAC_1 100n 24VAC_2 SPOOL TRIG NORM TRIG BC337-40...

  • Page 99: Appendix 5: Spool Gun Pcb

    FABRICATOR 251 MOT SPOOL MOT COM MOT LOC GV SPOOL GV COM GV LOC CON6 +35Vdc +35Vdc +35Vdc Install jumper for use with MILLER spool gun which has no speed pot on the spool gun 560R 1/2W 560R 1/2W 560R 1/2W AZ945 AZ945 AZ945...

  • Page 100: Appendix 6: Feedroll Kits

    FABRICATOR 251 APPENDIX 6: FEEDROLL KITS FEED ROLL KITS (#375980-Series) 2 ROLL Style 1 Style 2 Style 3 Style 4 Style 5 Style 6 Double Smooth Double Flat Flat Knurled "V" Knurled "V" Double Cog Double "U" Double Double Double Smooth Double Bottom Smooth "V"...

  • Page 102: Limited Warranty

    No employee, agent, or representative of Thermal Arc is authorized to change this warranty in any way or grant any other warranty, and Thermal Arc shall not be bound by any such attempt.

  • Page 103: Warranty Schedule

    WARRANTY SCHEDULE This information applies to Thermal Arc products that were purchased in the USA and Canada. April 2006 ENGINE DRIVEN WELDERS ARRANTY ERIOD ABOR Scout, Raider, Explorer Original Main Power Stators and Inductors .................. 3 years 3 years Original Main Power Rectifiers, Control P.C. Boards ..............3 years...

  • Page 105: Global Customer Service Contact Information

    GLOBAL CUSTOMER SERVICE CONTACT INFORMATION Thermadyne USA Thermadyne Asia Sdn Bhd 2800 Airport Road Lot 151, Jalan Industri 3/5A Denton, Tx 76207 USA Rawang Integrated Industrial Park - Jln Batu Arang 48000 Rawang Selangor Darul Ehsan Telephone: (940) 566-2000 West Malaysia 800-426-1888 Fax: 800-535-0557 Telephone: 603+ 6092 2988...
  • Page 106 World Headquarters Thermadyne Holdings Corporation Suite 300, 16052 Swingley Ridge Road St. Louis, MO 63017 Telephone: (636) 728-3000 Fascimile: (636) 728-3010 Email: sales@thermalarc.com www.thermalarc.com...

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