Lincoln Electric SQUARE WAVE TIG 255 Service Manual Download Page 63

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SQUARE WAVE TIG 255

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F-22

TROUBLESHOOTING & REPAIR

PROTECTION/SNUBBER BOARD CONTINUITY TEST

(continued)

Check Points

Component(s) Being Checked

Maximum Allowable Resistance

5J13 to 5J12

L1 and Board Trace

4.2 OHMS (3.3 Typical)

13J13 to 12J12

L2 and Board Trace

4.2 OHMS (3.3 Typical)

4J13 to 4J12

L3 and Board Trace

4.2 OHMS (3.3 Typical)

12J13 to 11J12

L4 and Board Trace

4.2 OHMS (3.3 Typical)

2J13 to 2J12

L5 and Board Trace

4.2 OHMS (3.3 Typical)

9J13 to 8J12

L6 and Board Trace

4.2 OHMS (3.3 Typical)

1J13 to 1J12

L7 and Board Trace

4.2 OHMS (3.3 Typical)

11J13 to 10J12

L8 and Board Trace

4.2 OHMS (3.3 Typical)

3J13 to 3J12

L9 and Board Trace

4.2 OHMS (3.3 Typical)

5J15 to 4J14

L10 and Board Trace

4.2 OHMS (3.3 Typical)

4J15 to 8J14

L11 and Board Trace

4.2 OHMS (3.3 Typical)

4J15 to 5J14

L12 and Board Trace

.35 OHMS (.32 Typical)

4J15 to 3J14

L13 and Board Trace

.35 OHMS (.32 Typical)

6J15 to 4J14

L10 and Board Trace

4.2 OHMS (3.3 Typical)

2J15 to 2J14

L14 and Board Trace

.35 OHMS (.32 Typical)

3J15 to 6J14

L15 and Board Trace

.35 OHMS (.32 Typical)

1J15 to 1J14

L16 and Board Trace

.35 OHMS (.32 Typical)

1J10 to 1J11

Board Trace

.0 OHMS

2J10 to 2J11

Board Trace

.0 OHMS

7J10 to 6J11

Board Trace

.0 OHMS

10J10 to 9J11

Board Trace

.0 OHMS

9J10 to 8J11

Board Trace

.0 OHMS

3J10 to 3J11

Board Trace

.0 OHMS

4J10 to 4J11

Board Trace

.0 OHMS

PROTECTION/SNUBBER

L9255

J10

J11

J12

J13

J14

J15

1J10

12J10

1J11

10J11

1J12

14J12

1J13

16J13

1J14

8J14

1J15

6J15

FIGURE F.6 - PROTECTION/SNUBBER BOARD TEST POINTS.

TABLE F.6

Summary of Contents for SQUARE WAVE TIG 255

Page 1: ...nstallation and thought ful operation on your part DO NOT INSTALL OPERATE OR REPAIR THIS EQUIPMENT WITHOUT READING THIS MANUAL AND THE SAFETY PRECAUTIONS CONTAINED THROUGHOUT And most importantly think before you act and be careful For use with machine Code Numbers 10022 For use with machine Code Numbers 10023 For use with machine Code Numbers 10024 For use with machine Code Numbers 10025 For use ...

Page 2: ...ding head nozzle or semiautomatic welding gun are also electrically hot 1 d Always be sure the work cable makes a good electrical connection with the metal being welded The connection should be as close as possible to the area being welded 1 e Ground the work or metal to be welded to a good electrical earth ground 1 f Maintain the electrode holder work clamp welding cable and welding machine in go...

Page 3: ...ting a fire Remember that welding sparks and hot materials from welding can easily go through small cracks and openings to adjacent areas Avoid welding near hydraulic lines Have a fire extinguisher readily available 4 b Where compressed gases are to be used at the job site special precautions should be used to prevent hazardous situations Refer to Safety in Welding and Cutting ANSI Standard Z49 1 ...

Page 4: ...________________________________ 7 c Do not add the fuel near an open flame welding arc or when the engine is running Stop the engine and allow it to cool before refueling to prevent spilled fuel from vaporizing on contact with hot engine parts and igniting Do not spill fuel when filling tank If fuel is spilled wipe it up and do not start engine until fumes have been eliminated ___________________...

Page 5: ...es de laitier en fusion sont émises de l arc de soudage Se protéger avec des vêtements de protection libres de l huile tels que les gants en cuir chemise épaisse pantalons sans revers et chaussures montantes 5 Toujours porter des lunettes de sécurité dans la zone de soudage Utiliser des lunettes avec écrans lateraux dans les zones où l on pique le laitier 6 Eloigner les matériaux inflammables ou l...

Page 6: ...tion B 8 B 11 Auxillary Power B 11 Overload Protection B 12 Accessories Section C Maintenance Section D Safety Precautions D 1 Routine and Periodic Maintenance D 1 General Assembly Exploded View D 2 Theory of Operation Section E Power Supply Operation E1 E 5 SCR Operation E 6 Thermal Protection E 7 Troubleshooting and Repair Section F How To Use Troubleshooting Guide F 1 PC Board Troubleshooting P...

Page 7: ... Dimensions Location A 2 Stacking A 2 Tilting A 2 High Frequency Interference Protection A 2 Input Connections A 3 Reconnect Procedure A 4 Output Connections A 4 Section A TABLE OF CONTENTS INSTALLATION SECTION SQUARE WAVE TIG 255 Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC ...

Page 8: ...rent Range Continuous 5 315 Amps AC and DC INPUT SINGLE PHASE ONLY RATED OUTPUT OUTPUT RECOMMENDED INPUT WIRE AND FUSE SIZES Input Voltage Frequency 208 60 230 60 460 60 575 60 200 50 60 220 50 60 380 50 60 400 50 60 415 50 60 440 50 60 500 50 60 Input Ampere Rating on Nameplate 81 74 37 30 85 77 46 43 41 39 34 Type 75 C Copper Ground Wire in Conduit AWG IEC Sizes 6 16mm2 8 10mm2 10 6mm2 10 6mm2 6...

Page 9: ...ound HIGH FREQUENCY INTERFERENCE PROTECTION The spark gap oscillator in the high frequency genera tor being similar to a radio transmitter can be blamed for many radio TV and electronic equipment interfer ence problems These problems may be the result of radiated interference Proper grounding methods can reduce or eliminate radiated interference Radiated interference can develop in the following f...

Page 10: ...e welder is enclosed in a metal building several good earth driven electrical grounds as in 5 b above around the periphery of the building are recommended Failure to observe these recommended installation procedures can cause radio or TV interference problems and result in unsatisfactory welding performance resulting from lost high frequency power FIGURE A 1 REAR PANEL 1 RATING PLATE 4 220V RECEPT...

Page 11: ...r these higher input currents However where unbalanced AC TIG welding above 180 amps is planned the higher input currents require larger input wire sizes and fuses Refer to Specification page at the beginning of this chapter The Square Wave TIG 255 should be permanently wired into the power system Plugs or connectors are not recommended 1Also called inverse time or thermal magnetic circuit breaker...

Page 12: ... precautions necessary for han dling and using compressed gas containers Contact your supplier for specific information ___________________________________________ Connect the TIG torch gas and water fittings to the welder fittings Any torch with fittings that conform to Compressed Gas Association CGA standards can be used The welder fittings have the following threads Gas Inlet and Outlet 5 8 18 ...

Page 13: ...rols B 7 Hand and Foot Amptrol Operation B 8 Welding Operation B 8 B 11 TIG Welding Guidelines B 8 TIG Welding Sequence of Operation 2 Step Mode B 9 TIG Welding Sequence of Operation 4 Step Mode B 10 Advanced Tig Welding Features B 11 Auxillary Power B 11 Overload Protection B 12 Section B TABLE OF CONTENTS OPERATION SECTION SQUARE WAVE TIG 255 Return to Master TOC Return to Master TOC Return to M...

Page 14: ...und Always wear dry insulating gloves FUMES AND GASES can be dangerous Keep your head out of fumes Use ventilation or exhaust to remove fumes from breathing zone WELDING SPARKS can cause fire or explosion Keep flammable material away Do not weld on containers that have held combustibles ARC RAYS can burn Wear eye ear and body protection OPERATING INSTRUCTIONS Read and understand entire section bef...

Page 15: ...n to Master TOC ON 2 A TIG 2 STEP TIG 4 STEP STICK CURRENT CONTROL OUTPUT LOCAL CUR RENT CON TROL REMOTE CUR RENT CON TROL INCREASE OUTPUT DECREASE HIGH FRE QUENCY CONTINUOUS HIGH FRE QUENCY START ONLY HIGH FRE QUENCY OFF CLEAN INCREASE POSITIVE POLARITY PENETRATE INCREASE NEGATIVE POLARITY TIG PULSER AFTERFLOW AFTERFLOW TIME GRAPHIC SYMBOLS THAT APPEAR ON THIS MACHINE OR IN THIS MANUAL HF ...

Page 16: ...OC OVER TEMPER ATURE INPUT POWER DC POLARITY DC POLARITY DO NOT SWITCH WHILE WELD ING WARNING WATER COOLANT OUTPUT WATER COOLANT INPUT WORK CONNEC TION GAS OUTPUT GAS INPUT ELECTRODE CONNECTION PROTECTIVE GROUND SINGLE PHASE TRANSFORMER AC DC RECTI FIER POWER SOURCE TIG GTAW SINGLE PHASE PULSED PER SECOND GRAPHIC SYMBOLS THAT APPEAR ON THIS MACHINE OR IN THIS MANUAL CONT AC POLARITY f AC WAVE BAL ...

Page 17: ...ion No tungsten spitting within current range of electrode Compact size requires only a 19 in x 30 in 485 mm x 760 mm footprint GENERAL DESCRIPTION The Square Wave TIG 255 is a constant current single range square wave AC DC TIG GTAW arc welding power source with built in high frequency stabilization It also has stick SMAW capability It is available from the factory in one model only there are no ...

Page 18: ...is locked out in the Stick mode Recessed panels protect controls output terminals gas and water fittings Large safety margins and protective circuits protect rectifiers from transient voltages and high currents Line Voltage Compensated Thermostatically Protected Electronic Over Current Protection WELDING CAPABILITY The Square Wave TIG 255 is rated at 255 amps 30 volts at 40 duty cycle on a ten min...

Page 19: ...ndicator lights are used to tell which functions are active and the display Item 1 is used to check the settings of the up down keys 1 WELD MODE KEYS These keys select the Weld Mode desired TIG 2 Step TIG 4 Step or Stick Read the complete Operating Instructions section for more information on TIG 2 Step and TIG 4 Step 2 CURRENT CONTROL These keys select Local or Remote and adjust the Amps Up or Am...

Page 20: ...NT CONTROLS Refer to Figure B 3 for the location of the following controls 1 POWER SWITCH Controls the input power to the Square Wave TIG 255 2 OVER TEMPERATURE LIGHT A yellow light which only lights when an over temperature situation occurs See the Maintenance Section for more information on the thermostatic protection 3 POLARITY SWITCH Selects DC AC or DC welding polarity DO NOT SWITCH UNDER LOA...

Page 21: ... used as arc start switches if Local Current Control is selected For simplicity the following explanation will refer only to Amptrols meaning both Foot and Hand models The term minimum refers to a Foot pedal in the up position as it would be with no foot pressure or a Hand Amptrol in the relaxed position with no thumb pressure Maximum refers to a fully depressed Foot Amptrol or a fully extended Ha...

Page 22: ...ing the Amps Up Down keys The output current setting will be displayed on the Ammeter 010 25 0 020 50 0 040 1 0 1 16 1 6 3 32 2 4 1 8 3 2 5 32 4 0 3 16 4 8 1 4 6 4 2 15 5 20 15 80 70 150 150 250 250 400 400 500 500 750 750 1000 3 3 3 10 20 15 30 25 40 40 55 55 80 80 125 2 15 5 15 10 60 50 100 100 160 150 210 200 275 250 350 325 450 2 15 5 20 15 80 70 150 140 235 225 325 300 400 400 500 500 630 2 1...

Page 23: ...iate a 5 second downslope The current will go down to a crater fill current that is equal to 25 of the welding current Release the Arc Start Switch to stop the arc and start the Afterflow timer After the Afterflow time has expired the gas and water valves will close To make another weld repeat steps 11 and 12 TIG WELDING SEQUENCE OF OPERATION 4 STEP MODE TIG 4 Step Mode funcitons like a trigger in...

Page 24: ...achine This circuit is protected from shorts and overloading by a 2 amp circuit breaker located above the receptacle The aux iliary circuit is intended for running water coolers whose current draw is within the 2 amp rating of the receptacle ADVANCED TIG WELDING FEATURES AC WAVE BALANCE AND AUTO BALANCE AC Wave Balance is a feature unique to square wave TIG power sources It is active only in AC TI...

Page 25: ...ave TIG 255 auxiliary for that equipment ___________________________________________ OVERLOAD PROTECTION This welder has thermostatic protection from excessive duty cycles overloads loss of cooling and high ambient temperatures When the welder is subjected to an overload or loss of cooling a thermostat will open This condition will be indicated by the illumination of the yellow Thermostatic Protec...

Page 26: ...B 13 NOTES SQUARE WAVE TIG 255 Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC ...

Page 27: ...C Available Option and Accessories C 1 Undercarriage Function C 1 Installation of Field Installed Options C 1 Section C TABLE OF CONTENTS ACCESSORIES SECTION Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC ...

Page 28: ... Square Wave TIG 255 lift bail is non functional Do not attempt to lift the power source with the undercarriage attached The undercarriage is designed for hand moving only mechanized towing can lead to injury and or damage to the Square Wave TIG 255 INSTALLATION OF FIELD INSTALLED OPTIONS Instructions for connecting the K932 1 Undercarriage and the K559 2 Magnum Cooler Horizontal TIG Mounting Brac...

Page 29: ...autions D 1 Routine and Periodic Maintenance D 1 General Assembly Exploded View D 2 Section D TABLE OF CONTENTS MAINTENANCE SECTION SQUARE WAVE TIG 255 Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC ...

Page 30: ...an the fol lowing components thoroughly See Figure D 1 for location of those components Main Transformer Output Terminals Polarity Switch Rectifier Assembly Control Box Assembly Spark Gap Assembly Protection PC Board Mounted to rear of control box assembly 3 Inspect welder output and control cables for fraying cuts and bare spots 4 Keep TIG torch and cables in good condition 5 The fan motor has se...

Page 31: ...C Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC FIGURE D 1 GENERAL ASSEMBLY EXPLODED VIEW 1 MAIN TRANSFORMER 5 CONTROL BOX ASSEMBLY 2 OUTPUT TERMINALS 6 SPARK GAP ASSEMBLY 3 POLARITY SWITCH 7 PROTECTION PC BOARD 4 RECTIFIER ASSEMBLY Mounted to rear of control box assembly 1 2 3 5 7 6 4 ...

Page 32: ...D 3 NOTES SQUARE WAVE TIG 255 Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC ...

Page 33: ... SWITCH R E C O N N E C T MAIN TRANSFORMER X2 X1 POWER FACTOR CAPACITORS FAN 115VAC PROTECTION SNUBBER BOARD ARC START 115 VAC GATE SIGNALS HI FREQ 115 VAC CONTROL BOARD LCD DISPLAY KEYPAD LED BOARD KEYPAD HIGH VOLTAGE TRANSFORMER CIRCUIT 115 VAC 115 VAC REMOTE RECEPTACLE 115 VAC RECEPTACLE CONTROL TRANSFORMER 24 VAC 18 VAC 16 VAC HIGH FREQUENCY SPARK WORK ELECTRODE HI FREQ TRANSFORMER BY PASS BOA...

Page 34: ...panel A reconnect panel allows the user to configure the machine for the desired input voltage This AC input voltage is applied to the primary of the main trans former Power factor correction capacitors are incor porated in the primary circuit of the main transformer to help balance the inductive nature of the TIG 255 The transformer changes the high voltage low current input power to a low voltag...

Page 35: ...C 16 VAC HIGH FREQUENCY SPARK WORK ELECTRODE HI FREQ TRANSFORMER BY PASS BOARD POLARITY SWITCH CHOKE FEED BACK GATE SIGNALS AC AC DC DC SCR BRIDGE SHUNT 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 volt age signal and fed back to the control board The control board compares the commands of the ke...

Page 36: ...PLAY KEYPAD LED BOARD KEYPAD HIGH VOLTAGE TRANSFORMER CIRCUIT 115 VAC 115 VAC REMOTE RECEPTACLE 115 VAC RECEPTACLE CONTROL TRANSFORMER 24 VAC 18 VAC 16 VAC HIGH FREQUENCY SPARK WORK ELECTRODE HI FREQ TRANSFORMER BY PASS BOARD POLARITY SWITCH CHOKE FEED BACK GATE SIGNALS AC AC DC DC SCR BRIDGE SHUNT The control board passes the 115vac through the pro tection snubber board to the primary of the high...

Page 37: ...ROL TRANSFORMER 24 VAC 18 VAC 16 VAC HIGH FREQUENCY SPARK WORK ELECTRODE HI FREQ TRANSFORMER BY PASS BOARD POLARITY SWITCH DC POSITION CHOKE FEED BACK GATE SIGNALS AC AC DC DC SCR BRIDGE SHUNT When the polarity switch is placed in either DC posi tion the AC voltage from the main transformer sec ondary is applied to the SCR bridge The SCR bridge and choke circuits are connected in a conventional fu...

Page 38: ...I FREQ TRANSFORMER BY PASS BOARD POLARITY SWITCH AC POSITION CHOKE FEED BACK GATE SIGNALS AC AC DC DC SCR BRIDGE SHUNT By rotating the polarity switch to the AC position the welding power circuit is changed One lead X2 of the main transformer secondary is connected to the machine s output work stud The other secondary lead X1 is connected to one of the AC connections on the SCR bridge The electrod...

Page 39: ...of the AC cycle time in the on state and the remainder of the time in the off state The amount of time spent in the ON state is controlled by the Gate An SCR is fired by a short burst of current into the gate This gate pulse must be more positive than the cathode voltage Since there is a standard PN junc tion between gate and cathode the voltage between these terminals must be slightly greater tha...

Page 40: ...mperature should occur the thermostat will prevent output voltage or current and the yellow indicator light will glow Additionally the display and keypad lights will turn off The fan will remain on during this period The thermo stat is self resetting once the machine cools sufficient ly If the thermostat shutdown is caused by excessive output or duty cycle and the fan is operating normally the pow...

Page 41: ...oscope Waveforms Normal Open Circuit Voltage Waveform DC Stick Mode F 31 Normal Open Circuit Voltage Waveform AC Stick Mode F 32 Normal Open Circuit Voltage Waveform DC TIG Mode F 33 Normal Open Circuit Voltage Waveform AC TIG Mode F 34 Typical Output Voltage Waveform Machine Loaded DC TIG Mode F 35 Typical Output Voltage Waveforms Machine Loaded AC TIG Mode F 36 Typical SCR Gate Voltage Waveform ...

Page 42: ...described in detail at the end of this chap ter Refer to the Troubleshooting and Repair Table of Contents to locate each specific Test Procedure All of the specified test points components terminal strips etc can be found on the referenced electrical wiring diagrams and schematics Refer to the Electrical Diagrams Section Table of Contents to locate the appropriate diagram HOW TO USE TROUBLESHOOTIN...

Page 43: ... PROCEDURES ELECTRIC SHOCK can kill Have an electrician install and service this equipment Turn the input power OFF at the fuse box before working on equipment Do not touch electrically hot parts WARNING 4 Test the machine to determine if the fail ure symptom has been corrected by the replacement PC board NOTE Allow the machine to heat up so that all electrical components can reach their operating...

Page 44: ...ltage must match the rating plate and reconnect the panel 3 Blown or missing fuses in input line 1 Check for proper input voltages As per nameplate and reconnect panel RECOMMENDED COURSE OF ACTION 1 Check input power switch S1 It may be faulty 2 Check for open or broken pri mary leads to main transformer T1 3 Check auxiliary 115vac power winding in the main transformer T1 1 Secondary thermostat ma...

Page 45: ... RECOMMENDED COURSE OF ACTION 1 Check for loose connectors at the SCR bridge and at the Protection Snubber board J10 and J11 See Figure F 2 at end of this Guide for location 2 Check the wiring to the Control Transformer T2 Observe directions on decal 3 The Protection Snubber board may be faulty See Protection Snubber Board Continuity Test 4 Check the Control Transformer T2 See Control Transformer ...

Page 46: ...e to machine 1 Welding application may exceed recommended duty cycle 2 Dirt and dust may have clogged the cooling channels inside the machine Blow out unit with clean dry compressed air 3 Air intake and exhaust louvers may be blocked due to inadequate clearance around machine 1 Inspect output stud insulators for cracks or signs of over heating RECOMMENDED COURSE OF ACTION 1 If voltage at the recep...

Page 47: ...SADJUSTMENT S None RECOMMENDED COURSE OF ACTION 1 The shunt leads 221 and 222 may be loose or open Check the red and white twist ed pair from the shunt to the control board Refer to wiring diagram 2 The Control board may be faulty If the shunt leads have continuity zero ohms to the control board pins 1J7 and 2J7 then replace the control board See pin locations in Figure F 1 at end of this Guide OU...

Page 48: ...NDED COURSE OF ACTION 1 Check the Keypad LED board to the Control board harness The plugs may be loose or defective 2 If only one red LED won t light the LED PC Board may be defective Replace 3 If three or more red LEDS do not light the Control board may be faulty Replace 1 Watch the Control Panel Display to see if the keys are responding properly to key presses If so then the Buzzer may be defect...

Page 49: ... 305 and 313C and their con nections to the machine output studs Refer to wiring diagram 2 The Control board may be faulty Check for machine open citcuit voltage at 5J6 and 12J6 on the Control board If open circuit voltage is pre sent then replace the Control board 3 If open circuit voltage is not present at 5J6 and 12J6 see Figure F 1 then check the Protection Snubber board See Protection Snubber...

Page 50: ...e None RECOMMENDED COURSE OF ACTION 1 Check leads 304 and 312 for proper connections Refer to wiring diagram 2 Check microswitch S2A located on polarity switch S2 for proper operation 3 The protection snubber board may be faulty See protection snubber board continuity test 4 Check control transformer T2 See control transformer voltage test 5 If above checks are OK then replace the control board 1 ...

Page 51: ... reduce the percentage of helium 4 Adjust flow rate of shielding gas 5 Check hoses and connections for leaks RECOMMENDED COURSE OF ACTION 1 Internal ground connections may be loose Check mounting screws on the Protection Snubber board and also on the Bypass board All case screws should be in place and tight 2 Protection Snubber board may be faulty See Protection Snubber Board Continuity Test 3 Che...

Page 52: ...s flow may be insufficient 3 Contaminated gas or faulty gas line or torch 1 Increase post flow time RECOMMENDED COURSE OF ACTION 1 SCR bridge may be faulty See Static and Active SCR Tests 2 Protection Snubber board may be faulty See Protection Snubber Board Continuity Test 3 Control board may be faulty Replace This may be a welding procedure problem Contact The Lincoln Electric Service Department ...

Page 53: ...good quality cables with a high natural rubber content such as Lincoln Stable Arc Cable Cables should be as short as possible 1 The arc start switch or amptrol may be defective There should not be any continuity between pins D and E on the arc start cable connector unless the unit is actuated 2 If an amptrol is not being used the machine must be in the Local Control Mode RECOMMENDED COURSE OF ACTI...

Page 54: ...1 In order for the high frequency to operate the machine must be either in the start only Mode or the continuous high frequency mode 2 The high frequency spark gap may be too large or shorted Check gap as per maintenance instructions RECOMMENDED COURSE OF ACTION This may be a welding procedure problem Contact The Lincoln Electric Service Department 216 383 2531 or 1 800 833 9353 WELD 1 Check the h...

Page 55: ...lters to prevent reoccurrence Consult your Local welder gas distributor 1 Tungsten electrode may be too small for process 2 Manual balance control may be misadjusted Readjust to the negative direction 3 If helium gas is being used reduce percentage of helium None RECOMMENDED COURSE OF ACTION Possible gas or water supply problem Contact The Lincoln Electric Service Department 216 383 2531 or 1 800 ...

Page 56: ...installed properly 2 If the output is low when the machine is in the Local Control Mode the problem could be internal to the machine 1 Check work and electrode cables for loose or poor connections 2 The weld cables may be too small or too long to permit the desired current to flow 3 The preset current adjustment may be set too low RECOMMENDED COURSE OF ACTION 1 Possible faulty SCR bridge See Stati...

Page 57: ...aster TOC Return to Master TOC F 16 TROUBLESHOOTING REPAIR SQUARE WAVE 255 CONTROL G2150 J1 J2 J3 J4 J5 J6 J7 J8 1J3 2J3 12J6 13J6 5J6 6J6 PROTECTION SNUBBER L9255 J10 J11 J12 J13 J14 J15 1J10 12J10 1J11 10J11 1J12 14J12 1J13 16J13 1J14 8J14 1J15 6J15 PC BOARD CONNECTOR LOCATIONS FIGURE F 2 PROTECTION SNUBBER BOARD CONNECTORS FIGURE F 1 CONTROL BOARD CONNECTORS ...

Page 58: ...e unable to perform the tests repairs safely contact the Lincoln Electric service department for technical troubleshooting assistance before you proceed call 216 383 2531 or 1 800 833 9353 WELD _____________________________________________________________________ If machine case sides and top are removed the case back and front must be support ed Failure to do this could result in mechanical or el...

Page 59: ...machine 2 Locate and remove Plug J8 from control board located in the control box Hint For ease of testing secure Plug J8 to case front with tape 3 Locate leads 432 and 433 connected to the control transformer T2 which is located in the top of the control box 4 Turn main power ON FIGURE F 3 LOCATION OF CONTROL BOARD AND CONTROL TRANSFORMER 5 Check for 120VAC at leads 432 to 433 A If 120VAC is pres...

Page 60: ... Proceed to protection snubber board continuity test B If resistance of any value is shown check wires and connections 8 Test for the correct AC voltages at Plug 8 See Figure F 4 A If one or more voltages are missing or incorrect control transformer is faulty Replace Secondary Approximate Lead Colors Plug P8 Voltages Red to Red 1 to 2 36 VAC Red to White 1 to 7 18 VAC Yellow to Yellow 4 to 10 16 V...

Page 61: ...incoln Electric factory trained person nel Unauthorized repairs performed on this equipment may result in danger to the technician or machine operator and will invalidate your factory warranty For your safe ty and to avoid electrical shock please observe all safety notes and precautions detailed throughout this manual If for any reason you do not understand the test procedures or are unable to per...

Page 62: ...F 5 3 The protection snubber board may be removed to simplify test A Remove three 8 32 x 1 4 Phillips head screws from bottom of board B Release board from nylon supports with needle nose pliers or small screw driver 4 Inspect board for leaky or burned components If questionable compo nents are observed then replace projec tion snubber board See note 5 Check resistances per Continuity Table F 6 A ...

Page 63: ... to 10J12 L8 and Board Trace 4 2 OHMS 3 3 Typical 3J13 to 3J12 L9 and Board Trace 4 2 OHMS 3 3 Typical 5J15 to 4J14 L10 and Board Trace 4 2 OHMS 3 3 Typical 4J15 to 8J14 L11 and Board Trace 4 2 OHMS 3 3 Typical 4J15 to 5J14 L12 and Board Trace 35 OHMS 32 Typical 4J15 to 3J14 L13 and Board Trace 35 OHMS 32 Typical 6J15 to 4J14 L10 and Board Trace 4 2 OHMS 3 3 Typical 2J15 to 2J14 L14 and Board Trac...

Page 64: ...y Lincoln Electric factory trained person nel Unauthorized repairs performed on this equipment may result in danger to the technician or machine operator and will invalidate your factory warranty For your safe ty and to avoid electrical shock please observe all safety notes and precautions detailed throughout this manual If for any reason you do not understand the test procedures or are unable to ...

Page 65: ...ity between pins 10J6 and 3J6 at plug J6 on the wiring har ness Refer to Figure F 8 If 8 4 ohms to 6 0 ohms resistance is indicated then arc start trigger circuit is okay If a high resistance or open is read then proceed to Step 5 Note If arc start switch is opened or jumper removed from pins D and E the measured resistance in Step 4 should be infinite 5 Test the resistance between 10J6 plug and 1...

Page 66: ...14 J15 10J12 3J12 3J13 11J13 6 Test the resistance from 11J13 on the projection snubber board to pin D on the six pin amphenol receptacle Lead 311 Also check resistance from 3J13 on the projection snubber board to pin E on the six pin amphenol receptacle Lead 303 FIGURE F 9 PROTECTION SNUBBER BOARD TEST POINTS FIGURE F 10 ARC START TRIGGER CIRCUIT A If zero ohms resistance is shown test is okay Pr...

Page 67: ... person nel Unauthorized repairs performed on this equipment may result in danger to the technician or machine operator and will invalidate your factory warranty For your safe ty and to avoid electrical shock please observe all safety notes and precautions detailed throughout this manual If for any reason you do not understand the test procedures or are unable to perform the tests repairs safely c...

Page 68: ...r to Figure F 11 3 Remove red insulating paint from heat sink test points See Figure F 12 DO NOT DISASSEMBLE THE HEAT SINKS 4 Using an analog ohmmeter test the resistance from anode to cathode of FIGURE F 11 PROTECTION BOARD PLUG LOCATIONS SCR1 ANODE CATHODE 1 2 SCR2 ANODE SCR3 CATHODE SCR4 CATHODE ANODE 3 4 PLUG P10 FIGURE F 12 SCR TEST POINTS SCR1 Reverse the meter leads and check from cathode t...

Page 69: ...nel Unauthorized repairs performed on this equipment may result in danger to the technician or machine operator and will invalidate your factory warranty For your safe ty and to avoid electrical shock please observe all safety notes and precautions detailed throughout this manual If for any reason you do not understand the test procedures or are unable to perform the tests repairs safely contact t...

Page 70: ...EDURE 1 Remove main supply power to machine 2 Remove plugs J10 and J13 from protec tion snubber board See Figure F 13 3 Remove red insulating paint from heat sink test points See Figure F 14 DO NOT DISASSEMBLE THE HEAT SINKS FIGURE F 13 PROTECTION SNUBBER BOARD PLUG LOCATIONS SCR1 ANODE CATHODE 1 2 SCR2 ANODE SCR3 CATHODE SCR4 CATHODE ANODE 3 4 PLUG P10 FIGURE F 14 SCR TEST POINTS 4 Perform test p...

Page 71: ...ximate ly 0 5 or 0 10 volts BATTERY TEST Check the battery by shorting leads A and C and then close switch SW 1 Re place battery if voltage is less than 4 5 volts 1 Connect SCR into the test circuit as shown A lead to anode C lead to cathode and G lead to the gate 2 Close switch SW 1 switch SW 2 should open voltmeter should read zero If the voltmeter reads higher than zero the SCR is shorted 3 Wit...

Page 72: ...l voltage and waveform checks with high frequency circuit OFF _____________________________________________________________________ 0 volts 50 volts 2ms CH1 This is the typical DC output voltage waveform generated from a properly operat ing machine Note that each vertical divi sion represents 50 volts and that each hori zontal division represents 2 milliseconds in time Note Scope probes connected ...

Page 73: ...ll voltage and waveform checks with high frequency circuit OFF _____________________________________________________________________ 0 volts 50 volts 2ms CH1 This is the typical AC output voltage wave form generated from a properly operating machine Note that each vertical division represents 50 volts and that each horizontal division represents 2 milliseconds in time Note Scope probes connected a...

Page 74: ... voltage and waveform checks with high frequency circuit OFF _____________________________________________________________________ 0 volts 50 volts 2ms CH1 This is the typical DC output voltage waveform generated from a properly operat ing machine Note that each vertical divi sion represents 50 volts and that each hori zontal division represents 2 milliseconds in time Note Scope probes connected a...

Page 75: ...l voltage and waveform checks with high frequency circuit OFF _____________________________________________________________________ 0 volts 50 volts 2ms CH1 This is the typical AC output voltage wave form generated from a properly operating machine Note that each vertical division represents 50 volts and that each horizontal division represents 2 milliseconds in time Note Scope probes connected at...

Page 76: ...F _____________________________________________________________________ 0 volts 20 volts 2ms CH1 This is a typical DC output voltage wave form generated from a properly operating machine Note that each vertical division represents 20 volts and that each horizontal division represents 2 milliseconds in time The machine was loaded with a resistance grid bank The TIG 255 display read 200 amps at 50VD...

Page 77: ...____________________________________________ 0 volts 20 volts 2ms CH1 These are typical AC output voltage wave forms generated from a properly operating machine Note each vertical division repre sents 20 volts and each horizontal division represents 2 milliseconds in time The machine was loaded with a resistance grid bank As the load is increased the output waveform becomes more square Note Scope ...

Page 78: ...checks with high frequency circuit OFF _____________________________________________________________________ 0 volts 2 volts 5ms CH1 This is the typical SCR gate pulse voltage waveform The machine was in an open circuit condition no load and operating properly Note that each vertical division represents 2 volts and that each horizontal division represents 5 milliseconds in time Note Scope probes c...

Page 79: ...th high frequency circuit OFF _____________________________________________________________________ 0 volts 50 volts 2ms CH1 This is NOT the typical DC output volt age waveform One output SCR is not functioning Note the gap in the wave form One SCR gate was disconnected to simulate an open or non functioning output SCR Each vertical division represents 50 volts and each horizontal division repre s...

Page 80: ...th high frequency circuit OFF _____________________________________________________________________ 0 volts 50 volts 2ms CH1 This is NOT the typical AC output voltage waveform One output SCR is not function ing Note the gap in the waveform One SCR gate was disconnected to simulate an open or non functioning output SCR Each vertical division represents 50 volts and each horizontal division represen...

Page 81: ...rs performed on this equipment may result in danger to the technician or machine operator and will invalidate your factory warranty For your safe ty and to avoid electrical shock please observe all safety notes and precautions detailed throughout this manual If for any reason you do not understand the test procedures or are unable to perform the tests repairs safely contact the Lincoln Electric se...

Page 82: ... THIS POINT THE RECTIFIER AND FAN BAFFLE ASSEMBLY WILL DROP UNLESS SUPPORTED Once the baffle assembly and case back are separated there is sufficient working space for fan blade and fan motor removal and replacement 6 The fan blade can be removed by loos ening the clamp on the fan blade and carefully sliding the fan blade off of the motor shaft Note When reinstalling the fan blade make certain the...

Page 83: ...on nel Unauthorized repairs performed on this equipment may result in danger to the technician or machine operator and will invalidate your factory warranty For your safe ty and to avoid electrical shock please observe all safety notes and precautions detailed throughout this manual If for any reason you do not understand the test procedures or are unable to perform the tests repairs safely contac...

Page 84: ...ain and lock washers from the four 1 4 20x1 75 hex head cap screws Remove the heat sink assem bly trying not to disturb the insulating washers and bushings See figure above 6 Reinstall the heat sink assembly in the same manner being certain that the insulating washers and bushings are installed correctly See figure above 7 Test with an ohmmeter to make certain that the heat sink assembly is electr...

Page 85: ... machines may be tested using 60 Hz power Input Volts Hertz Maximum Idle Amps 208 60 44 0 230 60 40 0 200 50 47 0 220 50 43 0 380 50 25 0 Voltage Across Power Factor 447 473 VAC Capacitors INPUT IDLE AMPS TIG Modes 5 Amps 12 Volts MAXIMUM ACCEPTABLE OUTPUT VOLTAGE AT MINIMUM OUTPUT SETTINGS TIG Modes 255 Amps 29 Volts MINIMUM ACCEPTABLE OUTPUT VOLTAGE AT MAXIMUM OUTPUT SETTINGS OPEN CIRCUIT VOLTAG...

Page 86: ...n to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC F 45 TROUBLESHOOTING REPAIR Test Points Voltages X1 X2 73 78 VAC X3 X4 230 232 116 122 VAC X3 X5 230 52A 217 228 VAC MAIN TRANSFORMER SECONDARY VOLTAGES See Figure F 16 FIGURE F 16 TRANSFORMER LEAD TEST POINTS RETEST AFTER REPAIR cont d ...

Page 87: ...tion G Control PC Board G2150 Components G 2 Protection Snubber PC Board L9255 Components G 6 Wiring Diagram G 9 Machine Schematic G 10 Control Board Schematic G2150 G 11 Control Board Schematic cont d G 12 Protection Snubber Board Schematic l9255 G 13 Keypad LED Board L9212 G 14 Section G TABLE OF CONTENTS ELECTRICAL DIAGRAMS ...

Page 88: ...ting PC Board repairs will invalidate your factory warranty Individual Printed Circuit Board Components are not avail able from Lincoln Electric This information is provided for reference only 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 Improper PC board repairs ...

Page 89: ...29 C30 CAPACITOR TAEL 27 35V 10 OCI1 OCI2 OCI3 OPTOCOUPLER PHOTO Q 70V OCI4 OCI5 OCI6 CNY17 3 X16 IC VOLT REG FIXED 3 T 1A 15V C3 C7 C10 C11 C12 CAPACITOR CEMO 0 1 50V 10 C14 C15 C33 C38 C45 C62 C69 C70 C72 C75 C78 C81 J5 CONNECTOR MOLEX MINI PCB 10 PIN J8 CONNECTOR MOLEX MINI PCB 12 PIN J6 CONNECTOR MOLEX MINI PCB 14 PIN DZ1 DZ6 DZ7 DZ10 ZENER DIODE 1W 30V 5 1N4751A DZ4 DZ5 DZ8 DZ9 ZENER DIODE 1W...

Page 90: ...ER TRIAC DRIVER ZVC 3083 X20 X21 X22 IC CMOS LATCH 3 STATE OCTAL HC573A TRI1 TRI2 TRI3 TRIAC T220 6A 800V R237 TRIMMER MT 1 2W 10K 10 LINEAR X31 X32 IC ARRAY CLAMPING PERIPHERAL R164 R235 RESISTOR WW 5W 150 5 SQ R7 RESISTOR MF 1 4W 133K 1 R230 R231 R232 RESISTOR MF 1 4W 26 7K 1 R233 R234 NOTE Lincoln Electric assumes no responsibility for liabilities resulting from board level troubleshooting PC B...

Page 91: ...G 5 NOTES SQUARE WAVE TIG 255 Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC ...

Page 92: ... Board repairs will invalidate your factory warranty Individual Printed Circuit Board Components are not avail able from Lincoln Electric This information is provided for reference only 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 Improper PC board repairs could r...

Page 93: ...danger to the Machine Operator or Technician Improper PC board repairs could result in damage to the machine PROTECTION SNUBBER BOARD L9255 C23 C24 C25 C26 CAPACITOR CEMO 4700P 50V 10 J15 CONNECTOR MOLEX MINI PCB 6 PIN J14 CONNECTOR MOLEX MINI PCB 8 PIN L1 L2 L3 L4 L5 L6 L7 CHOKE 390UH 5 225MA CONFORMAL L8 L9 L10 L11 R1 R2 R3 R4 RESISTOR CC 2W 47 10 J11 CONNECTOR MOLEX MINI PCB 10 PIN J10 CONNECTO...

Page 94: ...G 8 NOTES SQUARE WAVE TIG 255 Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC ...

Page 95: ... 3 5 2 3 2 B 2 2 9 A 2 3 9 A 2 3 9 2 3 5 A 2 3 8 A R 3 R 4 5 2 A CLEVELAND OHIO U S A C RW G2719 R WIRING DIAGRAM SQUARE WAVE TIG 255 Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC NOTE This diagram is for reference only It may not be accurate for all machines covered by thi...

Page 96: ... 12J3 13J3 14J3 15J3 16J3 4J3 5J3 7J3 3J3 6J3 8J3 R O W 1 R O W 2 R O W 3 1J1 2J1 3J1 4J1 5J1 6J1 7J1 8J1 C O L 4 C O L 3 C O L 2 C O L 1 1J2 5J2 3J2 7J2 9J2 ROW 1 ROW 2 ROW 4 ROW 5 2J2 4J2 6J2 8J2 9J11 4J12 11J12 5J12 12J12 2J12 8J12 1J12 3J12 3J15 2J15 6J15 1J15 5J15 4J15 4 3 2 4 3 3 4 3 2 B 4 3 5 4 3 6 4 2 9 4 3 2 A 2 3 2 A 2 3 3 2 2 9 2 3 7 2 3 5 2 3 6 3 0 3 3 1 1 3 0 1 3 0 9 3 0 2 3 1 3 C 3 0...

Page 97: ...1 15 0K R137 X10 3 4 2 6 7 R184 2 6 7 R 2 3 2 6 7 R185 4 0 V 6 0 0 m A Q17 D I S P L A Y C O M M O N L G N D X31GND N O I S Y C O M M O N N G N D IOGND X31 COMMON P R O C E S S O R I O C O M M O N X 3 2 C O M M O N L E G E N D GROUND AND 5V NETS L C D G N D L O G I C C O M M O N X 3 2 G N D P R O C E S S O R I O 5 V S U P P L Y X31 5V SUPPLY N O I S Y 5 V S U P P L Y L 5 V X 3 2 _ 5 V N 5 V L C D ...

Page 98: ...4 7 5 R103 1 00K R 2 2 8 G M T 2 MT1 TRI1 OCI9 2 6 1 4 OCI8 2 6 1 4 J 4 2 2 6 7 R107 1 00K R 2 2 7 IOGND L 5 V IO 5V IOGND N G N D N G N D N G N D N G N D N G N D 10K R125 J 4 5 4 7 5 R102 2 6 7 R106 D 0 5 0 V 0 1 C 7 8 X31 4 L G N D D 4 D 6 D 3 D 2 D1 D 7 D 0 D 7 D 5 1 00K R 6 8 L C D G N D J 3 8 J 3 14 R W 100 R162 100 R163 5 0 V 0 1 C 6 2 100V 100p C 5 7 4 75K R131 1 0A 3 0 V D 4 2 4 75K R130 X...

Page 99: ...ly applicable to your machine s specific PC board version This diagram is intended to provide general information regarding PC board function 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 Improper PC board repairs could result in damage to the machine Return to Sec...

Page 100: ...ble to your machine s specific PC board version This diagram is intended to provide general information regarding PC board function 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 Improper PC board repairs could result in damage to the machine Return to Section TOC R...

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