Home

Lincoln Electric SVM100-A User's Manual

1. NOTE Lincoln Electric assumes no responsibility for liabilities resulting from board level troubleshooting 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 could result in damage to the machine LINCOLN 5 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Return to Section TOC Ojo Fr amp un 818 EJE pio oO VU ojo Return to Section TOC Return to Master TOC Return to Master TOC ELECTRICAL DIAGRAMS G 3 Item X12 C22 032 C51 C52 C53 C54 C55 C56 C57 C58 C59 C60 C82 C83 C84 C85 C86 C5 C20 C25 C34 C41 C73 C74 C76 C77 C19 C21 J7 J4 J1 PTC1 PTC2 Identification IC VOLT REG FIXED 3 T 4 1A 5V CAPACITOR CEMO 22P 100V 5 CAPACITOR CEMO 100P 100V 5 022 50 20 150 100 5 CONNECTOR MOLEX MINI PCB 4 PIN CONNECTOR MOLEX MINI PC
2. 1 RATING PLATE 2 INPUT ENTRY HOLE 3 RECONNECT PANEL 4 220V RECEPTACLE amp BREAKER 50 60 HZ MACHINE ONLY 5 115V RECEPTACLE amp BREAKER GROUND CONNECTION The frame of the welder must be grounded A ground terminal marked with the symbol is located at the bottom of the input box for this purpose See your local and national electrical codes for proper grounding methods INPUT SUPPLY CONNECTIONS Have a qualified electrician connect single phase input power leads to L1 and L2 of the input panel in accor dance with all local codes and national electrical codes Refer to the connection diagram located on the inside of the cover of the Reconnect Panel LINCOLN Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo E un 818 EJE pI P oO VU cic Return to Section TOC Return to Master TOC INSTALLATION A 4 FIGURE A 2 FRONT PANEL RECONNECT PROCEDURE On multiple input voltage welders be sure the recon nect panel is connected per the following instructions for the voltage being supplied to the welder CAUTION Failure to follow these instructions can cause immedi ate failure of components within the welder Welders are shipped connected for the highest input voltage as listed on the rating Plate
3. F 32 9 Normal Open Circuit Voltage Waveform DC TIG Mode F 33 gt Normal Open Circuit Voltage Waveform AC TIG F 34 9 Typical Output Voltage Waveform Machine Loaded DC TIG Mode F 35 Typical Output Voltage Waveforms Machine Loaded TIG F 36 8 Typical SCR Gate Voltage Waveform 1 F 37 Abnormal Open Circuit Voltage Waveform DC Stick F 38 Abnormal Open Circuit Voltage Waveform AC Stick Mode F 39 Replacement Procedures Fan Motor and Blade Removal essen F 40 SCR Heatsink Assembly Removal sse F 42 Retest After Repair issues 44 Q 0 5 hw c a Retum to Master TOC SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo E El un 818 EJE plc cic Return to Section TOC Return to Master TOC F 1 TROUBLESHOOTING amp REPAIR HOW TO USE TROUBLESHOOTING GUIDE A WARNING 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 w
4. Ra diner D 1 Routine and Periodic Maintenance D 1 E General Assembly Exploded View D 2 Return to Master TOC Q FH 0 5 Ew c Retum to Master TOC SQUARE WAVE TIG 255 E MAINTENANCE MAINTENANCE SAFETY PRECAUTIONS A WARNING ELECTRIC SHOCK can kill Return to Section TOC Return to Master TOC Only qualified personnel should perform this maintenance Turn the input power OFF at the disconnect switch or fuse box before working on this equipment Do not touch electrically hot parts 5 5 3 8 ROUTINE AND PERIODIC ele MAINTENANCE HE A WARNING To avoid receiving a high frequency shock keep the TIG torch and cables in good condition 1 Disconnect power supply lines to machine before performing periodic maintenance 2 Periodically clean the inside of the machine with a low pressure air system Be sure to clean 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 rear of control box assembly Ojo Fr un 818 EJE pio cic 3 Inspect welder output and control cables for fraying cuts and bare spots 4 Keep TIG torch and cables in good
5. Return to Section TOC Return to Master TOC 10 1 00 550 3AVM AYVNDS Return to Section TOC Return to Master TOC OJo amp un 818 EJE oO VU cic
6. gt 8 8 This is NOT the typical DC output volt SCOPE SETTINGS age waveform One output SCR is not lo functioning Note the gap in the wave form One SCR gate was disconnected to Volts Div simulate an open or non functioning output Horizontal Sweep SCR Each vertical division represents 50 volts and each horizontal division repre sents 2 milliseconds in time Trigger Coupling Note Scope probes connected at machine output studs prove to electrode probe to work Return to Section TOC Return to Master TOC SQUARE WAVE TIG 255 F 39 TROUBLESHOOTING amp REPAIR ABNORMAL OPEN CIRCUIT VOLTAGE AC STICK MODE ONE OUTPUT SCR NOT FUNCTIONING A CAUTION HIGH VOLTAGE HIGH FREQUENCY can damage test equipment Perform all voltage and waveform checks with high frequency circuit OFF G T o n Return to Master CH1 oio dE 918 8 8 0 volts 2 2 2 cane 50 volts 2ms wc 918 0 n 8 8 This is the typical AC output voltage SCOPE SETTINGS 5 waveform One output SCR is not function 9 ing Note the gap in the waveform One SCR gate was disconnected to simulate an Volts Div open or non functioning output SCR Each Horizontal Sweep vertical division represents 50 volts and each horizontal division r
7. 4 Output 4 Return to Master Q FH 0 5 Ew c Retum to Master TOC SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fe un 818 EJE VU cic Return to Section TOC Return to Master TOC I INSTALLATION TECHNICAL SPECIFICATIONS SQUARE WAVE TIG 255 INPUT SINGLE PHASE ONLY Standard Input Current at Voltage Rated Output 1 208 230 460 1 60 81 74 37 230 460 575 1 60 74 37 30 200 240 400 1 50 60 85 77 44 220 380 440 1 50 60 77 45 39 380 41 5 500 1 50 60 45 41 33 220 380 415 1 50 60 77 45 41 RATED OUTPUT Duty Cycle Volts at Rated Amperes 40 Duty Cycle 30 NEMA Class II 40 60 Duty Cycle 28 100 Duty Cycle 26 OUTPUT Welding Current Range Constant Open Auxiliary Power Continuous Circuit Voltage 115 Volts AC 10 Amps 5 315 Amps Stick OCV 76 220Volts AC 2 Amps AC and DC TIG OCV 53 50 60 Hz machines only RECOMMENDED INPUT WIRE AND FUSE SIZES For all Stick DC TIG and Balanced AC TIG For Unbalanced AC TIG Welding Above 180 Welding at 255A 30V 40 Duty Cycle Amps 255A 16V 40 Duty Cycle Auto Based on the 1993 US National Balance Based on the 1993 U S National Electrical Code Electrical Code Type 75 C Type 75 C Fuse Input Type 75 C Copper Ground Typ
8. FIGURE F 9 PROTECTION SNUBBER BOARD TEST POINTS 918 EIE ala 9 2 6 Test the resistance from 11 13 on the A f zero ohms resistance is shown projection snubber board to pin D on test is okay Proceed to projection the six pin amphenol receptacle Lead snubber board test 311 Also check resistance from 3J13 on the projection snubber board to pin B If resistance of any value is shown E on the six pin amphenol receptacle check wires and connections Lead 303 Qio 5 918 9 un in Protection snubber Bd Control Board 8 8 Are Start Amphenol Switch Receptacle FIE zz 11 43 10 12 FIGURE F 10 ARC START TRIGGER CIRCUIT Ojo Fle els nile 918 2 pid cic LINCOLN 5 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr un 818 EJE pio cic Return to Section TOC Return to Master TOC LINCOLN 5 TROUBLESHOOTING amp REPAIR STATIC SCR TEST A WARNING Service and repair should only be performed by 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
9. bod gt 5 o WATER GAS 9 00000000 N 16 123 6 LATCH VIEW OF CONNECTOR ON PC BOARD 74 lem Return to Section TOC Return to Master TOC LINCOLN jo Return to Section TOC Return to Master TOC ELECTRICAL DIAGRAMS MACHINE SCHEMATIC SQUARE WAVE TIG 255 SCR4 CATHODE AC DC MICROSWITCH RODE SENSE WORK SENSE REMOTE CONTROL HIGH REMOTE CON N ARC STARTS ARC START SWITCH 432 115VAC 433 SCR4 CATHODE MAIN SCRI CA 5081 GATE JAIN RECTIFIER AC1 ATHODE MAIN RECTIFIER AC DC MICRI CH i ELECTRODE SENSE WORK SENSE REMOTE RECEPTACLE 301 6 303 f CONNECTION 302 U REMOTE o CURRENT lt 1 CONTROL k 8 o OPTIONAL AMPTROL Re CONTROL AND ARC START SW REMOTI ARC START SWITCH OUTPUT INDUCTOR SHUNT 400A 200mV SHUNT SHUNT MAIN TRANSFORMER CONNECT H5 RECONNEC PANEL 250 SEE NOTE A G 10 POLARITY SWITCH 52 2A 0 mMHaOR TN 115VAC FOR HI FREQ HI FREQ CONTROLI HI FREQ CONTROL 2 Return to Section TOC Return to Master TOC SHUNT SHUNT SHUNT TOROID L2 1 BUZZER TE VOLTAGE TRANSFORMER T3 200 100 LED HIGH FREQ TRANSFORMER NOTE A LEAD 250 FROM POWER FACTOR CAPACITORS CONNECTS ACCORDING THE THE INPUT VOLTAGE 208 230 460 200 380 440
10. 0 volts 50 volts 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 machine output studs probe to electrode probe to work LINCOLN 5 ams SCOPE SETTINGS Volts Div Horizontal Sweep Coupling Trigger SQUARE WAVE TIG 255 F 35 TROUBLESHOOTING amp REPAIR TYPICAL OUTPUT VOLTAGE WAVEFORM MACHINE LOADED DC TIG MODE A CAUTION HIGH VOLTAGE HIGH FREQUENCY can damage test equipment Perform all voltage and waveform checks with high frequency circuit OFF Return to Section TOC Return to Master TOC CH1 0 volts Return to Section TOC Return to Master TOC 20 volts ams MACHINE LOADED TO 200 AMPS AT 50 VDC This is a typical DC output voltage wave SCOPE SETTINGS form generated from a properly operating machine Note that each vertical division represents 20 volts and that each horizontal Volts Div division represents 2 milliseconds in time The machine was loaded with a resistance grid bank The TIG 255 display read 200 Coupling amps at 50VDC Trigger Ojo E El un 818 EJE plc cic Horizontal Sweep Note Scope probes connected at machine output studs probe to electrode pr
11. or DC AC is shown in Figure B 2 a DC is shown in Figure B 2 b B VOLTMETER This meter displays open circuit voltage as well as welding voltage as measured on the output studs of the Square Wave TIG 255 C AMMETER The ammeter can display preset current for setting the welding current before welding and actual welding current the value of the welding current during a weld D MOMENTARY DISPLAY This area is blank under most conditions see Figure B 2 a Different val ues may be displayed here as certain keypad keys are pressed See Figure B 2 b the TIG Pulser is being adjusted so the Pulse Frequency 2 0 Hz is being displayed Information in the Momentary Display lasts for five seconds after a key is pressed Read the complete Operating Instructions section for more information on the values that appear in the Momentary Display E BAR GRAPH DISPLAY This area provides a graphical display of values shown on the Ammeter SQUARE WAVE TIG 255 and on the Momentary Display When the Momentary Display is blank as in Figure B 2 a the Bar Graph Display represents values shown on the ammeter When a low value is shown on the ammeter only a few bars will appear on the left hand side of the Bar Graph Display As the ammeter value increases more and more bars will appear Whenever a value increases more and more bars will appear Whenever a value appears in the Momentary Display the Bar Graph Display w
12. safe distance from arc welding or cutting operations and any other source of heat sparks or flame Never allow the electrode electrode holder or any other electrically hot parts to touch a cylinder Keep your head and face away from the cylinder valve outlet when opening the cylinder valve Valve protection caps should always be in place and hand tight except when the cylinder is in use or connected for use Read and follow the instructions on compressed gas cylinders associated equipment and CGA publication Precautions for Safe Handling of Compressed Gases in Cylinders available from the Compressed Gas Association 1235 Jefferson Davis Highway Arlington VA 22202 FOR ELECTRICALLY powered equipment 6 a Turn off input power using the disconnect switch at the fuse box before working on the equipment Install equipment in accordance with the U S National Electrical Code all local codes and the manufacturer s recommendations Ground the equipment in accordance with the U S National Electrical Code and the manufacturer s recommendations Mar 93 SQUARE WAVE TIG 255 SAFETY FIELDS may be dangerous powered equipment 7 a Turn the engine off before troubleshooting and maintenance work unless the maintenance work requires it to be running 23 ELECTRIC AND MAGNETIC 8 a Electric current flowing through any conductor causes
13. LEAD 250 CONNECTS TO HIGH TERMINAL ON RECONNECT PANEL ALONG WITH CORRECT LEAD FROM MAIN TRANSFORMER T1 200 240 400 220 380 415 380 415 500 LEAD 4250 CONNECTS TO THE H5 LEAD OF ELECTRODE THE MAIN TRANSFORMER T1 Qjo C 15 918 un CIE y ce ojo 230 460 575 LEAD 250 CONNECTS TO THE MID TERMINAL ON THE RECONNECT PANEL ALONG WITH THE H3 LEAD FROM THE MAIN TRANSFORMER T1 KEYPAD LED PC BOARD a wre 9 SOLENOID E E SOLENOID 2308 2300 2294 ELECTRICAL SYMBOLS PER E1537 a LEAD COLORING CODE COMPONENT VALUE 118V 15A B BLACK UNITS SEEN CAPACITORS O ORANGE B RED MFD VOLTS U BLUE RESISTORS 115 VAC W WHITE OHMS WATTS RECEPTACLE 355 2 Y YELLOW C8 m CONNECTOR PIN NUMBERS 22 400V 22 400V 220 RECEPTACLE EXAMPLE THIS PIN IN rh 8 CONNECTOR 10 IS 6J10 50 60HZ MACHINES 74 16 LATCH VIEW OF CONNECTOR ON PC BOARD SQUARE WAVE TIG 255 SCHEMATIC MACHINE G 2736 Return to Section TOC Return to Master TOC NOTE This machine schematic is provided for reference only and may not be totally applicable to every code covered in this manual LINCOLN amp ELECTRIC SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC GIS eu un CIE y lo ojo Return to Section TOC Return to Master TOC ELECTRICAL
14. S This is the typical DC output voltage un olg waveform generated from a properly operat cle ing machine Note that each vertical divi 5 5 sion represents 50 volts and that each hori Volts Div zontal division represents 2 milliseconds in Hori ms orizontal Sweep Coupling Note Scope probes connected at machine Trigger output studs probe to electrode probe to work Return to Section TOC Return to Master TOC LINCOLN 5 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo E El un 818 EJE cic Return to Section TOC Return to Master TOC TROUBLESHOOTING amp REPAIR F 32 NORMAL OPEN CIRCUIT VOLTAGE WAVEFORM AC STICK MODE CAUTION HIGH VOLTAGE HIGH FREQUENCY can damage test equipment Perform all voltage and waveform checks with high frequency circuit OFF CH1 H4 HHH ett 0 volts 50 volts 2ms This is the typical AC output voltage wave SCOPE SETTINGS 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 machine output studs probe to electrode probe to work LINCOLN 5 Volts Div Horizontal Sweep Coupling Trigger SQUARE WAVE TIG
15. TL 2 2 Em TP I0GND 2 20 a 5 LOD 5V V V 10K 221K y AL 04 R52 RT Vj CUR FB 10 8 4 LCD CONTRAST CIRCUIT LCDGND lt lt 5 R50 ov ks Te SHUNT 22K 400A 200mV I0GND LCDGND gt gt NGND 3 82K id B 100p 100p 7 5 225290 3 82K T oV TO A482 1 LEGEND lt at GROUND AND 5V NETS IOGND PROCESSOR 10 COMMON LGND LOGIC COMMON NGND NOISY COMMON GENERAL INFORMATION LCDGND DISPLAY COMMON X31GND X31 COMMON HERWISE SPECIFIED SPECIFIED X32GND X32 COMMON SQUARE WAVE TIG 255 CONTROL BOARD N 5V NOISY 5V SUPPLY A4 8 2 2 01 03 94 LCD 5V DISPLAY 5V SUPPLY A X31_ 5V X31 5V SUPPLY X32_ 5V X32 5V SUPPLY NOTE Lincoln Electric assumes no responsibility for liabilities resulting from board level troubleshooting PC Board repairs will invalidate your factory warranty This Printed Circuit Board schematic is provided for reference only It may not be totally 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 des
16. 7 16 socket and box wrench 1 2 socket and box wrench 9 16 socket and box wrench ohmmeter multimeter Dow 340 heat sink compound F 42 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr un 818 EJE pio oO VU cic Return to Section TOC Return to Master TOC F 43 TROUBLESHOOTING amp REPAIR SCR HEAT SINK ASSEMBLY REMOVAL continued SCR Heat Sink Assemblies TEST PROCEDURE 1 2 Remove main power supply to machine Remove case sides and top Locate SCR heat sink assemblies Remove all gate snubber and cable leads from the SCR heat sink assembly that is to be serviced Remove the four 1 4 20 hex nuts and associated plain 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 Reinstall the heat sink assembly in the same manner being certain that the insulating washers and bushings are installed correctly See figure above SQUARE WAVE TIG 255 7 Test with an ohmmeter to make certain that the heat sink assembly is electrical ly isolated from chassis ground by at least 500 000 ohms of resistance Reconnect the gate leads Reconnect the snubber and cable leads using a thin coating of Dow 340 heat sink compound on the connection sur faces Be sure that th
17. Pulser circuit The TIG Pulser has On Off selections as well as adjustments for Pulses Per Second SQUARE WAVE TIG 255 OPERATION Up Down Adjustment of the pulses per second pulse frequency allows for control of the heat input into the work piece This adjustment can reduce distortion and burnthrough on thin guage base metal When the Pulser is turned On or when the Pulses Per Second are adjusted the pulse frequency is shown in the Momentary Display It can be varied from 0 5 Hz to 10 Hz in 0 5 Hz increments One Hertz Hz is equivalent to one pulse per second The background current the welding current at the low point of the pulse cycle is automatically adjusted from 40 to 60 of the peak current by the Square Wave TIG 255 The duty cycle the ratio between that time spent at the peak current vs the time spent at the background cur rent is fixed at 50 AUXILIARY POWER ALL MACHINES The Square Wave TIG 255 provides 10 amps of 115 volt AC power at a standard NEMA 5 15R receptacle located on the lower case back of the machine This circuit is protected from shorts and overloading by a 10 amp circuit breaker located next to the receptacle The auxiliary circuit is intended for running water cool ers and small power tools whose current draw is with in the 10 amp rating A CAUTION Note that some types of equipment especially pumps and large motors have starting currents which are sig nificantly higher than the
18. E 5 5 Input Line Voltage and Main Transformer E 1 9 Output Rectification and Feedback Control E 2 High Voltage High Frequency Circuit E 3 We lding 4 Welding Output E 5 SCR OperatOM M EE E 6 Thermal ProtectlOhi trot teret bte rne E 7 POWER SUPPLY BLOCK LOGIC DIAGRAM 2 FH E POLARITY BY PASS gt SWITCH BOARD E WORK HI FREQ 5 TRANSFORMER 5 2 ELECTRODE LINE SWITCH MAIN a TRANSFORMER E O x2 B 6 Q N N E C T o 2 5 Q lt 5 POWER FACTOR CAPACITORS 9 aa gt LCD DISPLAY E H18vaG PROTECTION E RE CONTROL KEYPAD GATE SIGNALS CORRE gt LED 5 BOARD 5 uma 115 VAC lt 4 amp CONTROL as 115 VAC TRANSFORMER EME RECEPTACLE PNA QO HIGH VOLTAGE 115 VA SNAC HIGH VOLTAGE HIGH FREQUENCY SPARK eee CIRCUIT RECEPTACLE NOTE On subsequent pages areas of this diagram that are the topic of discusstion are shown in white other portions of the circuit are shaded Retum to Master TOC SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr El un gis EJE pio cic Return to Section TOC Return to Master TOC E 1 THEORY OF OPERATION INPUT LINE VOLTAGE AND MAIN TRANSFORMER
19. POLARITY SWITCH LINE SWITCH MAIN TRANSFORMER E C e N N E C T E d POWER 9 it CAPACITORS E 9 115VAC PROTECTION ___5 VAC SNUBBER 115 VAC 0 115 RECEPTACLE CONTROL 115 VAC ARC START GATE SIGNALS HI FREQ TRANSFORMER BY PASS BOARD WORK O HI FREQ TRANSFORMER O ELECTRODE o lt m IE gt LCD DISPLAY CONTROL KEYPAD gt LED BOARD KEYPAD REMOTE RECEPTACLE The desired single phase input power is connected to the TIG 255 through a line switch located on the front 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 voltage high current output In addition the main transformer also has an isolated SQUARE WAVE TIG 255 HIGH VOLTAGE TRANSFORMER HIGH FREQUENCY SPARK CIRCUIT 115vac auxiliary winding that supplies 115vac to operate the cooling fan and offers 10 Amps of auxil iary power at the 115vac receptacle This 115vac is also applied to the control board and the control trans former via the protection snubber boar
20. amp m POLARITY FIER POWER SOURCE ak DO NOT Al SWITCH HE h WHILE WELD LE TIG GTAW 8 8 ING I a N WARNING SINGLE PHASE Lara WORK CONNEC 2 COOLANT A TION OUTPUT HE WATER AC POLARITY 2 COOLANT TV JE INPUT LINCOLN 5 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo E El un 818 EJE oO VU cic Return to Section TOC Return to Master TOC OPERATION 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 factory installed options only variations in input voltage and frequency The Square Wave TIG 255 includes advanced features such as Auto Balance 2 Step 4 Step Arc Start Switch operation and a TIG pulser In addition fixed preflow and variable afterflow timers are included for shielding gas and cooling water control RECOMMENDED PROCESSES AND EQUIPMENT The Square Wave TIG 255 is recommended for the TIG GTAW and stick SMAW welding processes within its output capacity of 5 to 315 amps on both AC and DC polarity It is compatible with all Magnum TIG accessories see Accessory section in this manu al as well as many industry standard it
21. detailed throughout this manual If for any reason you do not understand the test procedures are 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 CAUTION If machine case sides and top removed the case back and front must be support ed Failure to do this could result in mechanical or electrical damage to the TIG 255 TEST DESCRIPTION The Active SCR Test will determine if the device is able to be gated ON and conduct current from anode to cathode MATERIALS NEEDED An SCR tester as outlined in this procedure TIG 255 Wiring Diagrams see Electrical Diagrams section of this manual SCR Heat Sink Assembly Drawing Figure F 14 F 28 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr 8 un 818 EJE pio oO VU cic Return to Section TOC Return to Master TOC F 29 TROUBLESHOOTING amp REPAIR ACTIVE SCR TEST continued REMOVE PLUGS J10 amp J13 PROTECTION SNUBBER 19255 3 d
22. fan motor for maintainence or replacement TOOLS REQUIRED 3 8 socket wrench or nutdriver 10 long screwdriver slot head 5 16 open end or box wrench F 40 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr un 818 EJE pio oO VU cic Return to Section TOC Return to Master TOC F 41 TROUBLESHOOTING amp REPAIR FAN MOTOR AND BLADE REMOVAL continued Fan Baffle TEST PROCEDURE 1 2 Remove main supply power to machine Remove case sides and top Locate and SUPPORT rectifier and fan baffle assembly Remove the two self tapping screws from the input access door Remove the five thread forming screws holding the fan baffle and rectifier assembly to the case back AT 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 SQUARE WAVE TIG 255 Mounting Hardware Vertical Bracket 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 blade is on the motor shaft in the correct location Approximately 25 past end of shaft If the fan motor is to be removed the leads to the motor must be d
23. 255 F 33 TROUBLESHOOTING amp REPAIR NORMAL OPEN CIRCUIT VOLTAGE WAVEFORM DC TIG MODE A CAUTION HIGH VOLTAGE HIGH FREQUENCY can damage test equipment Perform all voltage and waveform checks with high frequency circuit OFF Return to Section TOC Return to Master TOC CH1 0 volts T o n Eus i d Return to Master TOC 50 volts 2ms wc 918 gt 8 8 This is the typical DC output voltage SCOPE SETTINGS E waveform generated from a properly operat glo ing machine Note that each vertical divi sion represents 50 volts and that each hori Volts Div zontal division represents 2 milliseconds in Horizontal Sweep time Coupling Note Scope probes connected at machine Trigger output studs probe to electrode probe to work Return to Section TOC Return to Master TOC LINCOLN 5 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr un 818 EJE cic Return to Section TOC Return to Master TOC TROUBLESHOOTING amp REPAIR F 34 NORMAL OPEN CIRCUIT VOLTAGE WAVEFORM AC TIG MODE CAUTION HIGH VOLTAGE HIGH FREQUENCY can damage test equipment Perform all voltage and waveform checks with high frequency circuit OFF CH1
24. 5 SQUARE WAVE TIG 255 TROUBLESHOOTING amp REPAIR F 18 CONTROL TRANSFORMER T2 VOLTAGE TEST continued SUPORT CASE BACK AND CENTER BAFFLE CONTROL BOX WITH WOOD 2 X 4 CONTROL BOARD LOCATED INSIDE gt CONTROL TRANSFORMER LOCATED INSIDE Return to Section TOC Return to Master TOC 2 o n 9 i 3 4 oc Return to Master TOC FIGURE F 3 LOCATION OF CONTROL BOARD AND CONTROL TRANSFORMER TEST PROCEDURE 5 Check for 120VAC at leads 432 to 433 1 Remove main supply power to machine z A If 120VAC is present at leads 432 Fle 2 Locate and remove Plug J8 from control to 433 go tolstep 8 6 5 board located in the control box Hint 9 For ease of testing secure Plug J8 to Note If main supply voltage varies case front with tape control transformer voltages will 8 8 vary accordingly E 3 Locate leads 432 and 433 connected 9 to the control transformer T2 which is B If a very low or zero voltage is located in the top of the control box shown at leads 432 to 433 then go to Step 6 4 Turn main power ON 6 Remove main supply power to machine Return to Section TOC Return to Master TOC SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr un 818 EJE cic Return to Section TOC Return to Master TOC idis TROUBLESHOOTING amp REPAIR C
25. Display will be blank and all of the red Control Panel lights will be out The fan will continue to run to cool the power source No welding is possible until the machine is allowed to cool and the Thermostatic Protection Light goes out Return to Section TOC Return to Master TOC Ojo Fr B un 818 EJE pI P cic Return to Section TOC Return to Master TOC SQUARE WAVE TIG 255 LINCOLN Z NOTES SQUARE WAVE TIG 255 B 13 DOL 03 5 W 03 20 5 W 5 W 03 DOL uon2es DOL uon2es WNJPY 301 uon2es WNJPY 301 2 5 TABLE OF CONTENTS Section C ACCESSORIES SECTION H g 8 POU OS 5 ORNS M PR Section Available Option and Accessories cscsssssssesescscscseresesesescscsssesesescececateteeeeeees C 1 Undercarriage Function iii C 1 E Installation of Field Installed Options C 1 Return to Master TOC Q FH 0 5 Ew c Retum to Master TOC SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr un 818 EJE pio oO VU cic Return to Section TOC Return to Master TOC SQUARE WAVE TIG 255 ACCESSORIES OPTIONS ACCESSORIES Hand
26. LINCOLN 5 5 10 11 12 Select Continuous High Frequency if welding with AC polarity or Start Only High Frequency if welding with DC polarity High Frequency Off can be used for scratch start welding Select AC or DC electrode polarity See Table B 1 If welding with AC polarity select Auto Balance This gives the optimum ratio between cleaning and penetration automatically adjusted for the output current If manual adjustment of the AC Wave Balance is desired select Manual Balance and adjust the wave balance with the Cleaning and Penetration keys See the Advanced Features section for more information on setting and using the AC Wave Balance Select TIG Pulser On or Off If the TIG Pulser is on adjust the pulse frequency with the Pulses Per Second Up Down keys See the Advanced Features section for more information on setting and using the TIG Pulser Set the Afterflow time with the Seconds Up Down keys Afterflow time provides shielding gas flow and cooling water if used after the weld Use short Afterflow times with low currents and small tungstens long afterflow times at high output currents with large tungstens Press and release the Arc Start Switch and set the gas flow meter The welder is now ready for welding Position the tungsten electrode at the start of the weld at a 65 to 75 angle with the horizontal so that the electrode is approximately 1 8 4mm above the work piece Press the Arc
27. OF RECOMMENDED SYMPTOMS MISADJUSTMENT S COURSE OF ACTION TIG MODE PROBLEMS Lack of penetration in AC TIG Manual balance control set 1 SCR bridge may be faulty See welding improperly set to negative and Active SCR Tests 10 10 for maximum penetration Protection Snubber board may be faulty See Protection Snubber Board Continuity Test Control board may be faulty Replace Return to Section TOC Return to Master TOC Black areas along weld bead Tungsten electrode may be This may be a welding procedure contaminated Replace or problem sharpen Contact The Lincoln Electric Shielding gas flow may be Service Department 216 383 insufficient 2531 or 1 800 833 9353 WELD Return to Section TOC Return to Master TOC Contaminated gas or faulty gas line or torch Black areas along weld bead at or Increase post flow time This may be a welding procedure near end of weld problem Contact The Lincoln Electric Service Department 216 383 2531 or 1 800 833 9353 WELD Ojo Ec un 818 EJE 0 cic CAUTION 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 216 383 2531 or 1 800 833 9353 LINCOLN 5 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC TROUBLESHOO
28. Sizes for Combined Lengths of Copper Electrode and Work Cable Lengths up to Machine Size 100 ft 100 to 200 ft 200 to 250 ft 255 Amp 40 Duty Cycle 2 35mm 1 45mm 1 0 55mm2 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 right hand female Water inlet and Outlet 5 8 18 left hand female The cylinder of inert shielding gas must be equipped with a pressure regulator and flow meter Install a hose between the flow meter and gas inlet on the welder WARNING Observe the safety precautions necessary for han dling and using compressed gas containers Contact your supplier for specific information DO NOT operate a water cooled torch unless water is flowing Water doesn t flow until solenoid is actuated If using a water cooled torch with a Magnum water cooler connect the cooler water outlet to the Water Valve In fitting Connect the TIG torch inlet to the Water Valve Out fitting If using a water cooled torch with a free running water supply install a water line between the welder Water Inlet and the supply Include a strainer in the water supply line to prevent dirt particles from obstructing water flow in the valve and cooling chamber of the TIG torch Failure to do so could result in water valve ma
29. Start Switch This opens the gas and water valves to automatically purge air from the hose and torch After a 0 5 second preflow time the high frequency becomes available to strike the arc Hold the Arc Start Switch down until an arc is established The arc will start at a low current value Release the Arc Start Switch At this point the Square Wave TIG 255 will quickly ramp up to the welding current and the weld will continue indefinitely Press the Arc Start Switch a second time to initiate 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 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo E El un 818 EJE pj 21 VU cic Return to Section TOC Return to Master TOC B 11 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 TIG mode It controls the amount of positive and negative current in the AC output The Square Wave TIG 255 allows the operator to select Auto Balance This selection provides automatic adjustment of the AC Wave Balance it is suitable f
30. at least eight feet into the ground The ground should be securely made and the grounding cable should be as short as possible using cable of the same size as the work cable or larger Grounding to the building frame electrical conduit or a long pipe system can result in re radiation effectively making these members radiating antennas 6 Keep all access panels and covers securely in place 7 All electrical conductors within 50 ft 15 2m of the welder should be enclosed in grounded rigid metallic conduit or equivalent shielding Flexible metallic conduit is generally not suitable 8 When the 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 INPUT CONNECTIONS Be sure the voltage phase and frequency of the input power is as specified on the rating plate located on the rear of the machine Refer to Figure A 1 Welder supply line entry provision is in the case rear panel with a removable cover over the input connection panel area Entry is through a 1 7 in 43mm diameter hole in the case back See Figure A 1 SQUARE WAVE TIG 255 INSTALLATION FIGURE A 1 REAR PANEL o
31. condition 5 The fan motor has sealed ball bearings which require no maintenance 6 Inspect spark gap spacing at regular intervals to maintain a 0 015 in 0 4mm gap Smallest possible air gap consistent with good welding is desirable to minimize R F I problems Dressing or any refinishing of the spark gap contacts is not recommended If the contact surfaces become irregular or completely eroded replacement of both electrodes is recommended LINCOLN 5 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC MAINTENANCE oe FIGURE D 1 GENERAL ASSEMBLY EXPLODED VIEW Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo E El un 818 EJE cic Q E E 5 9 un o 1 MAIN TRANSFORMER 5 CONTROL BOX ASSEMBLY c 2 OUTPUT TERMINALS 6 SPARK GAP ASSEMBLY 5 3 POLARITY SWITCH 7 PROTECTION PC BOARD U 4 RECTIFIER ASSEMBLY Mounted to rear of control box assembly aic SQUARE WAVE TIG 255 LINCOLN Z NOTES SQUARE WAVE TIG 255 D 3 DOL 03 5 W 03 20 5 W 5 W 03 DOL uon2es DOL uon2es WNJPY 301 uon2es WNJPY 301 2 5 TABLE OF CONTENTS Section E THEORY OF OPERATION SECTION Q g Theory of Operation Section Section E p Power Supply Operation sui 1
32. current increases LINCOLN 5 8 8 CONTROL AND DISPLAY AREA 5 OPTIONAL WATER SOLENOID 1 2 POWER SWITCH 6 GAS SOLENOID 3 THERMOSTATIC 7 WORK LEFT AND PROTECTION LIGHT ELECTRODE TERMINALS 4 POLARITY SWITCH 8 REMOTE RECEPTACLE OUTPUT CONNECTIONS A WARNING To avoid receiving a high frequency shock keep the TIG torch and cables in good condition See Figure A 2 for the location of the work and electrode terminals the gas and optional water solenoids and the Remote Receptacle TIG TORCH CONNECTION TIG welding torches come with 12 5 ft 3 8m and 25 ft 7 6m cables Use the shorter length whenever possible to minimize possible radio interference problems With power source off connect the torch cable to the Electrode terminal on the welder Connect a separate work cable to the Work terminal of the welder See Table for recommended work cable sizes Both work and electrode cables should be routed through the cable strain relief holes provided in the base directly below the welding output terminals SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr un 818 EJE pio oO VU cic Return to Section TOC Return to Master TOC A 5 TABLE A 1 Cable
33. 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 LINCOLN 5 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr un 818 EJE pio oO VU cic Return to Section TOC Return to Master TOC G 4 ELECTRICAL DIAGRAMS CONTROL BOARD G2150 cont d Item Identification X19 IC UNDERVOLTAGE SENSING RESET MCU X10 IC CMOS INVERTER SCHMITT HEX HC14A C65 C66 CAPACITOR TAEL 4 7 35V 10 X11 X14 IC OP AMP QUAD HIGH PERF 33074A C49 C67 C68 CAPACITOR CD 0047 3000V 20 DZ13 DZ14 DZ15 ZENER DIODE 1W 12V 5 1N4742A DZ16 DZ17 J2 CONNECTOR PCB WW MALE DIL 1X9 X15 REGULATOR amp HEATSINK ASBLY D10 D11 D21 D22 DIODE AXLDS 1A 1000V C79 C80 CAPACITOR CD 750P 1000V 10 R33 RESISTOR MF 1 4W 301 1 Y1 CRYSTAL QUARTZ 8 000MHZ 8 9 10 OPTOCOUPLER TRIAC DRIVER ZVC 3083 X20 X21 X22 IC CMOS LATCH 3 STATE OCTAL HC573A TRH TRI2 TRIS 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 t
34. for defective plugs or loose wires The Control board may be faulty Replace Ojo Ec un 818 EJE 0 cic A CAUTION 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 216 383 2531 or 1 800 833 9353 LINCOLN 5 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC TROUBLESHOOTING amp REPAIR F 10 TROUBLESHOOTING GUIDE Observe Safety Guidelines detailed in the beginning of this manual PROBLEMS SYMPTOMS POSSIBLE AREAS OF MISADJUSTMENT S TIG MODE PROBLEMS RECOMMENDED COURSE OF ACTION Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr un 818 EJE Bio oOo VU cic Machine output is intermittently lost Gas flow and high frequency are also interrupted Arc Flutters when TIG welding Problem may be caused by high frequency interference Make sure that the machine is grounded properly according to the installation instructions If there are other high frequency sources in the area make certain that they are grounded properly Check arc start switch or amptrol for proper operation and loose connections Tungsten electrode may be too large in diameter Tungsten not Sharp when
35. opens the gas and water valves to automati cally purge air from the hose and torch After a 0 5 second preflow time the high frequency becomes available to strike the arc 12 Hold the Arc Start Switch or Amptrol down until an arc is established If using an Amptrol read the section on Hand and Foot Amptrol Operation Release the Arc Start Switch or Amptrol 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 interlock making it unnecessary to hold down the Arc Start Switch during welding By depressing the Arc Start Switch a first time the arc will start at a low current step 1 By releasing the Arc Start Switch step 2 the output ramps up to welding current Depressing the Arc Start Siwtch a second time step 3 initiates a welding current downslope Releasing the Arc Start Switch step 4 stops the arc Hence the name 4 Step Mode 1 Connect an Arc Start Switch to the Remote Receptacle 2 Turm the welder gas supply and water supply if so equipped on The Control Panel Display and red lights will illuminate when the power is on 3 Select the TIG 4 Step Weld Mode 4 Select the Local current control Set the output current using the Amps Up Down keys The output current setting will be displayed on the Ammeter
36. 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 216 383 2531 or 1 800 833 9353 WELD CAUTION 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 electrical damage to the TIG 255 TEST DESCRIPTION The Static SCR Test is a quick check to determine if an SCR is shorted or leaky See machine waveform section or normal and abnormal SCR waveforms MATERIALS NEEDED Analog ohmmeter Multimeter TIG 255 Wiring Diagrams see Electrical Diagrams section of this manual SCR Heat Sink Assembly Drawing Figure F 12 F 26 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr 8 un 818 EJE pio oO VU cic Return to Section TOC Return to Master TOC F 27 TROUBLESHOOTING amp REPAIR STATIC SCR TEST continued REMOVE PLUGS J10 amp J13 PROTECTION SNUBBER L9255 BEN UN FIGURE F 11 PROTECTION BOARD PLU
37. to simplify setup Examples the AC wave balance control has no effect in DC the High Frequency and gas and water valves do not operate in Stick mode TIG Pulser 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 Return to Section TOC Return to Master TOC 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 minute basis It is capable of higher duty cycles at lower output currents If the duty cycle s are exceeded a thermal protector will shut off the output until the machine cools to a reasonable operating temperature Ojo Fr 2 un 818 EJE pio oO VU cic LIMITATIONS The Square Wave TIG 255 is not recommended for arc gouging due to its limited output capacity The Square Wave TIG 255 is not recommended for AC TIG welding when high concentrations of helium are used for shielding starting problems and arc recti fication may occur The Square Wave TIG 255 is not recommended for pipe thawing LINCOLN 5 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC OPERATION B 6 CONTROLS AND SETTINGS All operator controls and adjustments are located on the case fron
38. welding in DC negative mode If helium is used as a shielding gas then reduce the percentage of helium Adjust flow rate of shielding gas Check hoses and connections for leaks 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 Protection Snubber board may be faulty See Protection Snubber Board Continuity Test Check trigger circuit See Ard Start Trigger Circuit Test Check for loose shunt connec tions leads 221 and 222 Refer to wiring diagram Check polarity switch for loose or faulty connections SCR bridge may be faulty See and Active SCR Tests Protection Snubber board may be faulty See Protection Snubber Board Continuity Test Check R3 R4 and C2 in the high voltage transformer prima ry circuit Refer to wiring dia gram The Control board may be faulty Replace A CAUTION 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 216 383 2531 or 1 800 833 9353 LINCOLN 5 Return to Section TOC Return to Master TOC SQUARE WAVE TIG 255 F 11 TROUBLESHOOTING amp REPAIR TROUBLESHOOTING GUIDE Observe Safety Guidelines detailed in the beginning of this manual PROBLEMS POSSIBLE AREAS
39. 16 in 11 mm 8 1 2 in 12 5 mm 10 5 8 in 16 mm 5 TIG torch nozzles are typically made from alumina ceramic Special applications may require lava nozzles which are less prone to breakage but cannot with stand high temperatures and high duty cycles TIG WELDING SEQUENCE OF OPERATION 2 STEP MODE 5 Select Continuous High Frequency if welding with AC polarity or Start Only High Frequency if welding with DC polarity High Frequency Off can In TIG 2 Step Mode the welding arc is established by be used for scratch start welding depressing the Arc Start Switch or Amptrol Step 1 Output continues as long as the switch or Amptrol is depressed Releasing the switch or Amptrol Step 2 turns off the arc Hence the name 2 Step Mode 6 Select AC or DC electrode polarity See Table B 1 Ojo Fr un gis EJE pio oO VU cic 7 If welding with AC polarity select Auto Balance This gives the optimum ratio between cleaning and penetration automatically adjusted for the output current If manual adjustment of the AC Wave Balance is desired select Manual Balance and adjust the wave balance with the Cleaning and Penetration keys See the Advanced Features section for more information on setting and using the AC Wave Balance 1 Connect an Arc Start Switch or an Amptrol to the Remote Receptacle 2 Turn on the welder gas supply and water supply if so equipped The Control Pa
40. 2 RU Al n ERER mE EA 22009 JJ 919 NOTE NOTE TN IJ5 CONNECTS TO 6 CONNECTS TO OUTPUT INDUCTOR 1 JI J2 A 44 J5 Je SEE NOTE BELOW 4328 06 POWER FACTOR CORRECTION CAPACITORS Bi 250 SHUNT 2 5 CONNECTS 2J6 CONECTS TO 232 1 1 TO 2 ETC a N Pa c5 CONTROL PC BOARD REAR GANG OF POLARITY SWITCH 305 NOTE LEAD 250 FROM POWER FACTOR CAPACITORS CONNECTS ACCORDING THE THE INPUT VOLTAGE 208 230 460 200 380 440 LEAD 250 CONNECTS TO HIGH TERMINAL ON RECONNECT PANEL ALONG WITH CORRECT LEAD FROM MAIN TRANSFORMER 304 N S2A MICRO SWITCH IN AC POSITION OPEN IN AC CLOSED IN DC 312 Return to Section TOC Return to Master TOC 200 240 400 380 415 500 220 380 415 LEAD 250 CONNECTS TO THE H5 LEAD OF THE MAIN TRANSFORMER R2 52 3134 218 338 230 460 575 LEAD 250 CONNECTS TO THE MID TERMINAL POLARITY SWITCH 1 1 1 ON THE RECONNECT PANEL ALONG WITH THE ci 2 JE J 5 5 9 5 JE 8 5 D s H3 LEAD FROM THE MAIN TRANSFORMER TD VI
41. 974 jamais enrouler le c ble lectrode autour de n importe quelle PR CAUTIONS DE S RET POUR partie du corps LES MACHINES SOUDER Un coup d arc peut tre plus s v re qu un coup de soliel TRANSFORMATEUR ET REDRESSEUR donc a Utiliser un bon masque avec un verre filtrant appropri ainsi qu un verre blanc afin de se prot ger les yeux du rayonnement de l arc et des projections quand on soude ou quand on regarde l arc Porter des v tements convenables afin de prot ger la peau de soudeur et des aides contre le rayonnement de l arc Prot ger l autre personnel travaillant proximit au soudage l aide d crans appropri s et non inflamma bles Relier la terre le chassis du poste conformement au code de l lectricit et aux recommendations du fabricant Le dis positif de montage ou la piece souder doit tre branch une bonne mise la terre Autant que possible l installation et l entretien du poste seront effectu s par un lectricien qualifi Avant de faires des travaux l interieur de poste la Des gouttes de laitier en fusion sont mises de l arc de soudage Se prot ger avec des v tements de protection libres de l huile tels que les gants en cuir chemise paisse pantalons sans revers et chaussures montantes debrancher l interrupteur la boite de fusibles Garder tous les couvercles et dispositifs de s ret leur place Mar 93 LIN
42. Amptrol K812 Foot Amptrol K870 Arc Start Switch K814 Magnum Cooler Horizontal TIG Mounting Bracket K559 2 Undercarriage K932 1 UNDERCARRIAGE FUNCTION The Square Wave TIG 255 is designed to be used with a Lincoln K932 1 Undercarriage Complete installation instructions are included with the K932 1 undercarriage When the undercarriage is properly installed the 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 Bracket are included with those acces sories Installation of the K812 Hand Amptrol the K814 Arc Start Switch and K870 Foot Amptrol are as follows Lift the Output Cover Door if so equipped on the Square Wave TIG 255 Feed the cable up through the strain relief holes in the base and connect the 6 pin MS type Amphenol connector to the Remote Receptacle Secure with the thread ed collar LINCOLN TABLE OF CONTENTS Section D MAINTENANCE SECTION g 8 Maintenance i roi opt pO EDU au Ee Section D Safety Precautions seilicet
43. B 6 PIN CONNECTOR MOLEX MINI PCB 8 PIN THERMISTOR PTC 56 OHMS 90MA D1 D2 D3 D4 D5 D6 D7 DIODE AXLDS 1A 400V D18 D19 D20 D23 D24 D25 D30 D34 D37 D38 D39 D40 D41 D43 D44 D45 D46 D47 D48 D49 D50 D51 D52 D53 D54 D55 D56 D57 D58 D59 D71 D72 D73 D74 D75 D76 D77 D78 D79 D80 D81 D92 D99 D100 D101 L1 L2 L3 16 635 C23 044 C47 C48 C71 C43 C27 C28 C29 C30 2 OCI4 0CI5 0C16 X16 C3 C7 C10 C11 C12 C14 C15 C33 C38 C45 C62 C69 C70 C72 C75 C78 C81 J5 J8 J6 DZ1 DZ6 DZ7 DZ10 DZ4 DZ5 DZ8 DZ9 Q1 Q3 Q5 Q8 Q10 Q11 Q13 Q14 Q16 Q17 Q2 Q4 Q6 Q12 D42 CHOKE 330UH 1096 110MA MOLDED CHOKE 390UH 5 225MA CONFORMAL CAPACITOR TAEL 18 15V 10 CAPACITOR TAEL 1 0 35V 10 CAPACITOR ALEL 20 50V 75 10 CAPACITOR TAEL 27 35V 10 OPTOCOUPLER PHOTO Q 70V CNY17 3 IC VOLT REG FIXED 3 T 1A 15V CAPACITOR CEMO 0 1 50V 10 CONNECTOR MOLEX MINI PCB 10 PIN CONNECTOR MOLEX MINI PCB 12 PIN CONNECTOR MOLEX MINI PCB 14 PIN ZENER DIODE 1W 30V 5 1N4751A ZENER DIODE 1W 18V 5 1N4746A TRANSISTOR N T226 0 5A 40V 2N4401 TRANSISTOR NMF 4PDIP 1A 100V RFD110 DIODE AXLDS 1A 30V SCHOTTKY Item C42 R14 R17 R18 R21 R24 R26 R109 R154 R155 R156 R157 R158 R159 R160 R162 R163 R168 R169 R170 R171 R182 R183 R20 R25 R41 R56 R57 R68 R69 R74 R77 R84 R87 R91 R92 R93 R94 R112 R113 R114 R115 R118 R120 R123 R124 R127 R129 R140 R144 R214 R225 R226 R227 R228 R229 R9 R22 R49 R76
44. CAUTION HIGH VOLTAGE HIGH FREQUENCY damage test equipment Perform all voltage and waveform checks with high frequency circuit OFF Return to Section TOC Return to Master TOC CH1 0 volts T o n Eus i d Return to Master TOC 2 volts 5ms Qio cate wc 918 Qi Ae 818 This is the typical SCR gate pulse voltage SCOPE SETTINGS waveform The machine was in an open 910 circuit condition load operating cic properly Note that each vertical division Volts Div represents 2 volts and that each horizontal ll Horizontal Sweep division represents 5 milliseconds in time Coupling Note Scope probes connected at SCR Trigger gate and cathode probe to gate probe to cathode Return to Section TOC Return to Master TOC LINCOLN 5 SQUARE WAVE TIG 255 TROUBLESHOOTING amp REPAIR F 38 ABNORMAL OPEN CIRCUIT VOLTAGE DC STICK MODE ONE OUTPUT SCR NOT FUNCTIONING CAUTION HIGH VOLTAGE HIGH FREQUENCY can damage test equipment Perform all voltage and waveform checks with high frequency circuit OFF G T o n Return to Master CH1 Qio 5 918 0 abs 918 Hi 0 volts gle 8 9 50 volts 2ms Ojo wc 918
45. COLN 5 SQUARE WAVE TIG 255 v RETURN TO MAIN INDEX MASTER TABLE OF CONTENTS FOR ALL SECTIONS Page Safety RAT i iv Installation 1 cn Section A Technical Specifications sus A 1 LOCATION pm A 2 High Frequency Interference Protection A 2 Input tacui duced cat ci rete cert Hen aere to rade A 3 Output Cofinections terreri dte rie Free ivi Melted A 4 enum Section B Safety Precautions sise B 1 Graphic 2 3 General 4 0 4 sir B 4 Design Features and Advantages B 4 Welding Capability sise B 5 LIMNATIONS carora B 5 Controls and Settings us B 6 Hand and Foot Amptrol Operation ss B 8 Welding Operation B 8 B 11 Auxillary o B 11 Overload Protection coss essetis eadera coque B 12 Cm Section Maint nahCe i Section D Safety eit aes invented D 1 Routine and Periodic D 1 General Assembly Exploded View D 2 Theory of Section Power Supp
46. DIAGRAMS G 11 CONTROL BOARD SCHEMATIC SQUARE WAVE TIG 255 G2150 TO A482 2 ELECTRODE 5 s 54022202 1 00M R39 cag SA 5 E LEGEND 0047 GROUND AND 5V NETS _ _ C79 Voltage FB 750p 1000V 106 0 PROCESSOR 10 COMMON 076 E NGND LGND LOGIC COMMON bi WORK Kie E rj es NGND NOISY COMMON C80 69 TE TIR i 5 LCDGND DISPLAY COMMON 00 P 0716 2 X31GND X31 COMMON Db 50V 29 X82GND X32 COMMON C28 IOGND 2 10 5V 10 5V PROCESSOR 10 5V SUPPLY B 35V 12 L 5V LOGIC 5V SUPPLY N 5V NOISY 5V SUPPLY woo V LCD 5V DISPLAY 5V SUPPLY E EH ZERO CROSS X31_ 5V X81 45V SUPPLY 600m 5 2 40V X32 45V X32 5V SUPPLY n Di SCR 1 GATE Di gt gt SCR 2 GATE R214 D hs D52 D59 bs TIK al C65 099 T00K cat A 145 LOD45V X31 45V X32 5V m
47. EWED FROM BACK IN AC POSITION i o 1 1 1 q 305A JI2 JIO Jil Ci ARC STABILIZER CAPACITOR 4 220 2324 c2 PHASE SHIFT CAPACITOR 15 250 SECONDARY c3 HIGH VOLTAGE CAPACITOR 0015 12k V THERMOSTAT J 4 5 POWER FACTOR CAPACITORS 50 460 230A 233 de 2 C6 C7 HI FREO PROTECTION CAPS 22 400 e C8 C9 HI FREQ PROTECTION CAPS 0047 3kV 2308 1 1 CIRCUIT BREAKER IO AMP 230F 233A cu CB2 CIRCUIT BREAKER 2 AMP l Yo J DI FREE WHEELING DIODE PEN 1 LI OUTPUT INDUCTOR 7 T4 BYPASS 1 PROTECTION SNU i L2 HI FREQ PROTECTION CHOKE PC BOARD 1314 HI FREQ INDUCTORS RI HOLDING CURRENT RESISTOR 50 100 R2 ARC STABILIZING RESISTOR 25 25 235 R3 R4 PHASE SHIFT RESISTOR 200 100 SI INPUT POWER SWITCH lt 52 POLARITY SWITCH ELECTRODE none 3 S2A MICROSWITCH ON POLARITY SWITCH t 236A SCRL2 3 4 MAIN SCRs SVISV2 GAS amp WATER SOLENOIDS TI MAIN TRANSFORMER m 238A R4 OPTIONAL REMOTE T2 CONTROL TRANSFORMER AMPTROL AND ARC HIGH VOLTAGE TRANSFORMER START SWITCH T4 HI FREQ TRANSFORMER 30 2 e o gt 309 2 EMOTE RECEPTACLE O gt 0 0 2 0 gt 302 o s M gt 303 IOK PEDAL UP 236 PUSERO
48. FIGURE F 13 PROTECTION SNUBBER BOARD PLUG LOCATIONS TEST PROCEDURE 4 Perform test procedure as outlined in Figure F 15 Repeat test for all four 1 Remove main supply power to machine SCR s 2 Remove plugs J10 and J13 from protec 5 Replace any SCR assembly that does tion snubber board See Figure F 13 not pass test in Step 4 3 Remove red insulating paint from heat sink test points See Figure F 14 DO NOT DISASSEMBLE THE HEAT SINKS SCR3 CATHODE SCR2 ANODE CATHODE SCR4 CATHODE FIGURE F 14 SCR TEST POINTS LINCOLN 5 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr un 818 EJE pio oO VU cic Return to Section TOC Return to Master TOC LINCOLN 5 TROUBLESHOOTING amp REPAIR F 30 ACTIVE SCR TEST continued SW1 R2 Low 6volt Lantern Battery R1 4 ohms 10 watts R2 3 ohms 10 watts 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 FIGURE F 15 SILICON CONTROLLED RECTIFIER TEST SETUP SILICON CONTROLLED BATTERY TEST RECTIFIER TEST Heat Sink Mounted Units Check the battery by shorting leads A and C and then close switch SW 1 Re place To test SCR s construct the circu
49. FTER REPAIR cont d Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC X2 To polarity switch FIGURE F 16 TRANSFORMER LEAD TEST POINTS MAIN TRANSFORMER SECONDARY VOLTAGES See Figure F 16 Test Points Voltages X1 X2 73 78 VAC Ojo E El un 818 EJE cic X4 230 232 116 122 VAC X5 230 52A 217 228 VAC Return to Section TOC Return to Master TOC LINCOLN 5 SQUARE WAVE TIG 255 TABLE OF CONTENTS Section G ELECTRICAL DIAGRAMS Q g Electrical Diagrams eese annee nnns Section G p Control PC Board G2150 Components G 2 5 Protection Snubber PC Board 19255 Components G 6 9 Wining EM G 9 Machine SCHOM AUG tercer coo onde nettes G 10 Control Board Schematic 62150 G 11 Control Board Schematic cont d iaaii aaa G 12 Protection Snubber Board Schematic 19255 G 13 Keypad LED Board L9212 sse G 14 Return to Master TOC Q H 0 5 hw c a Retum to Master TOC SQUARE WAVE TIG 255 ee ELECTRICAL DIAGRAMS CONTROL BOARD G2150
50. G LOCATIONS TEST PROCEDURE 1 2 Remove main supply power to machine Remove plug J10 and J13 from the pro tection snubber board Refer to Figure F 11 Remove red insulating paint from heat sink test points See Figure F 12 DO NOT DISASSEMBLE THE HEAT SINKS Using an analog ohmmeter test the resistance from anode to cathode of SCR2 ANODE CATHODE SCR1 Reverse the meter leads and check from cathode to anode of SCR1 A If a low resistance is indicated in either direction SCR1 is faulty Replace SCR assembly Repeat Step 4 testing SCR2 SCR3 and SCR4 To further check the SCR s functions use an SCR tester and proceed to active SCR test CATHODE SCR4 CATHODE FIGURE F 12 SCR TEST POINTS SQUARE WAVE TIG 255 LINCOLN Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr un 818 EJE pio cic Return to Section TOC Return to Master TOC LINCOLN 5 TROUBLESHOOTING amp REPAIR ACTIVE SCR TEST A WARNING Service and repair should only be performed by 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
51. Gas Flow Rate 2 5 Unbalanced Wave Balanced Wave C F H 1 min 01 9 Tungsten 1 2 1 2 c Electrode 1 2 1 2 Thoriated Thoriated TIG Torch 5 5 Diameter Thoriated Thoriated Pure Tungsten Pure Tungsten Stainless Nozzle 9 Tungsten Tungsten Tungsten Zirconiated Tungsten Zirconiated Size n 2 15 2 15 2 15 2 15 4 5 6 5 20 5 15 5 20 10 20 5 20 15 80 10 60 15 80 20 30 20 60 70 150 50 100 70 150 30 80 60 120 3 5 5 6 150 250 100 160 140 235 60 130 100 180 13 17 6 8 6 7 8 250 400 150 210 225 325 100 180 160 250 15 23 7 11 5 5 400 500 200 275 300 400 100 240 200 320 21 25 10 12 8 10 FE 500 750 250 350 400 500 190 300 290 390 23 27 11 13 750 1000 325 450 500 630 250 400 340 525 28 32 13 15 45 o a 1 When used with argon gas The current ranges shown must be reduced when using argon helium or pure helium shielding gasses in gt 2 Tungsten electrodes are classified as follows by the American Welding Society AWS olo PUN EWP 1 EWTh 1 2 EWTh 2 Though not yet recognized by the AWS Ceriated Tungsten is now widely accepted as a substitute for 2 Thoriated Tungsten in and DC applications E 3 DCEP is not commonly used in these sizes 4 TIG torch nozzle sizes are in multiples of 1 16ths of an inch 4 1 4 in 6 mm 5 5 16 in 8 mm 6 3 8 in 10 mm 7 7
52. Held Hazardous Substances AWS F4 1 from the American Welding Society see address above Vent hollow castings or containers before heating cutting or welding They may explode Sparks and spatter are thrown from the welding arc Wear oil free protective garments such as leather gloves heavy shirt cuffless trousers high shoes and a cap over your hair Wear ear plugs when welding out of position or in confined places Always wear safety glasses with side shields when in a welding area Connect the work cable to the work as close to the welding area as practical Work cables connected to the building framework or other locations away from the welding area increase the possibility of the welding current passing through lifting chains crane cables or other alternate cir cuits This can create fire hazards or overheat lifting chains or cables until they fail 4 h Also see item 7c LINCOLN 5 CYLINDER may explode if damaged 5 a Use only compressed gas cylinders containing the correct shielding gas for the process used and properly operating regulators designed for the gas and pressure used All hoses fittings etc should be suitable for the application and maintained in good condition B Always keep cylinders in an upright position securely chained to an undercarriage or fixed support Oylinders should be located Away from areas where they may be struck or subjected to physical damage
53. J5 J5 SCR ICATHODE 7 SCR 2CATHODE LE Dot 10 5V gt gt gt gt 7 010 J8 p AUX 8683 LES AUX SCR4 D47 D48 E 15V 01 065 16VAC 1 of XFMR 5 00 100 5 _ 0 100 oo 126 05 D4 j zs d Le a 006 Ed gt gt ey gt AUX SCR4 lt lt li 17 3 C67 047 0047 peu 10 T 021 3000 T TT AU GS 1W CT y 238 36VAC CT lt lt m gt SCR3GATE pi Jy y SCR4 GATE L aL c4 8000 T ZU afio lt lt x1 48 Da SCR sCATHODE iN ane out 8 CR 80A 158 7915 DS gt SCR Dt 50V SS eS SS SS 092 024 ic 8 NGND LGND 600mA 18V 40V VB LCDGND X31GND R63 I0GND X32GND IOGND 16VAC f mum 57 GENERAL INFORMATION CAPACITOR MFD 022 50V UNLESS OTHERWISE SPECIFIED RESISTORS ns 1 4W UNLESS OTHERWISE SPECIFIED 16VAC x31 DIODES 14 4000 UNLESS OTHERWISE SPECIFIED 120VAC ci 07 Tio C69 0 0 iiid ow 40 SQUARE WAVE TIG 255 CONTROL BOARD 50V 744057 50V HS 50V 2 33074A AL 33074A aL 06 4 8 2 1 01 03 94 1 om 50V 50V A IOGND 36VAC C T 10680 X32 LGNDLGNDLGND V cono i 15V CONTROL TRANSFORMER NOTE Lincoln Electric assumes no responsibility for liabilities resulting from board level troubles
54. MANUAL BALANCE ll s o o o ea 0 18 1 ci 3 2 3 3 G A 19 CONNECTS TO Wh i 1 1 1 A F START CLEAN HF START ONLY 2 CONNECTS TO 22 4 STEP este 1 1 GIS 9 un CIE y ce ojo AFTER FLOW 4 1 4 2 4 3 4 4 1 2 AMPS PULSES PER SEC PENETRATE H F OFF KEYPAD LEAD COLORING CODE COMPONENT VALUE m B BLACK UNITS 230E G GREEN CAPACITORS b ORANGE MFD VOLTS 229 2300 e Fan e 2328 MACHINES ONLY CB2 U BLUE RESISTORS 5 1 5 3 5 4 W WHITE OHMS WATTS 2308 CBI D usvac 6665 5609 Y YELLOW 229 KE EI LED 230 pura ce CONNECTOR PIN NUMBERS ag m 3l 220VAC KEYPAD LED PC BOARD KEYPAD MATRIX CONNECTION ROW COL 56 5i EXAMPLE THIS PIN IN sv svi 4 CONECTOR JIO 15 6JIO 232 5 50 60 HZ u un 0000 m VIEWED FROM BACK 9 52A LINCOLN E L E R CLEVELAND OHIO U S A G2719 NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual The specific diagram for a particular code is pasted inside the machine on one of the enclosure panels
55. N Keep flammable material away Do not weld on containers that have held combustibles 4 5 VE Wear eye ear and body protection Observe additional Safety Guidelines detailed in the beginning of this manual LINCOLN OPERATION B 2 GRAPHIC SYMBOLS THAT APPEAR ON THIS MACHINE OR IN THIS MANUAL Return to Section TOC Return to Master TOC TIG 2 STEP AFTERFLOW Aa AFTERFLOW TIG4 STEP CONTINUOUS HE HIGH FRE a CURRENT START ONLY HE gt CONTROL HF _ HIGHFRE HE OUTPUT QUENCY LOCAL CUR OFF RENT CON TROL ON REMOTE CUR RENT CON TROL CLEAN 0 INCREASE 4S a0 POSITIVE INCREASE POLARITY Ojo Fr un 818 EJE Bio v cic 0 INCREASE x 200 NEGATIVE DECREASE POLARITY A GF OUTPUT PENETRATE V TIG PULSER HF HIGH FRE JUL QUENCY Return to Section TOC Return to Master TOC SQUARE WAVE TIG 255 ES OPERATION GRAPHIC SYMBOLS THAT APPEAR ON THIS MACHINE OR IN THIS MANUAL CONT AC WAVE BAL x G T o n Return to Master ANCE i5 GAS OUTPUT f PULSED PER lt D GAS INPUT ELECTRODE ug ATURE f CONNECTION INPUT E PROTECTIVE HE D GROUND 8 E DC 55 POLARITY SINGLE PHASE TRANSFORMER DC 1
56. NG Service and repair should only be performed by 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 Return to Section TOC Return to Master TOC 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 216 383 2531 or 1 800 833 9353 WELD CAUTION 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 electrical damage to the TIG 255 Return to Section TOC Return to Master TOC TEST DESCRIPTION This test will determine if the correct voltage is being applied to the primary of the con trol transformer and also if the correct voltages are being induced on the secondary windings of the transformer MATERIALS NEEDED Volt Ohmmeter Multimeter TIG 255 Wiring Diagrams See Electrical Diagram Section of manual Table of Voltage Tests and Drawing of Transformer and Molex Plug J8 Figure F 4 Ojo Fr un 818 EJE pio cic Return to Section TOC Return to Master TOC LINCOLN
57. NOKE N ea a LL gt LCD DISPLAY CONTROL KEYPAD BOARD gt LED BOARD KEYPAD HIGH VOLTAGE TRANSFORMER HIGH FREQUENCY SPARK CIRCUIT the control board and applied to the SCR bridge through the protection snubber board The control board controls the firing of the SCRs thus controlling the output of the machine See SCR Operation The control board also powers and commands the keypad LED board and the display board SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Ojo E a un gis EJE ojo Return to Section TOC Return to Master TOC Return to Master TOC E 3 THEORY OF OPERATION HIGH VOLTAGE HIGH FREQUENCY CIRCUIT POLARITY BYTAS SWITCH WORK HI FREQ TRANSFORMER O ELECTRODE LINE i SWITCH MAIN 7 TRANSFORMER x2 AC DC E SCR BRIDGE N N E DC 1 22 val 3 5 dj 5 a POWER 9 FACTOR w CAPACITORS 9 ARC START gt I LCD DISPLAY 115 VAC me 0 e GATE SIGNALS BOARD d DOARE KEYPAD 115 VAC D CONTROL 115 TRANSFORMER RECEPTACLE RSA e HIGH VOLTAGE 115 VAC TRANSFORMER PIGH FREQUENCY SPARK REMOTE CIRCUIT RECEPTACLE The control board passes the 115vac through the pro tection snubber board to the primary of the high volt age transformer The secondary of the high voltage transformer is coupled to a spa
58. OC Return to Section TOC Return to Master TOC Ojo E El un 818 EJE cic Return to Section TOC Return to Master TOC TROUBLESHOOTING amp REPAIR F 22 PROTECTION SNUBBER BOARD CONTINUITY TEST continued 1J10 1J11 1J12 1J13 1J14 1J15 PROTECTION SNUBBER m 19255 J10 J11 J12 13 14 15 12J10 10J11 14J12 16J13 8J14 6J15 FIGURE F 6 PROTECTION SNUBBER BOARD TEST POINTS Check Points Component s Being Checked Maximum Allowable Resistance 5J13 to 5412 L1 and Board Trace 4 2 OHMS 3 3 Typical 13413 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 12413 to 11J12 L4 and Board Trace 4 2 OHMS 3 3 Typical 2J13 to 2 12 L5 and Board Trace 4 2 OHMS 3 3 Typical 9J13 to 8012 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 5J15 to 4J14 4J15 to 8014 L10 and Board Trace L11 and Board Trace 4 2 OHMS 3 3 Typical 4 2 OHMS 3 3 Typical 4J15 to 5J14 L12 and Board Trace 35 OHM
59. OCK 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 CAUTION Sometimes machine failures appear to be due to PC board failures These problems can sometimes be traced to poor electrical connections To avoid problems when troubleshooting and replac ing PC boards please use the following procedure 1 Determine to the best of your technical ability that the PC board is the most like ly component causing the failure symp tom 2 Check for loose connections at the PC board to assure that the PC board is properly connected 3 If the problem persists replace the sus pect PC board using standard practices to avoid static electrical damage and electrical shock Read the warning inside the static resistant bag NOTE It is desirable to have a spare known good PC board available for PC board troubleshooting 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 temperature 5 Remove the replacement PC board and substitute it with the original PC board to recreate the original problem a If the original problem does not reap pear by substituting the original board then the PC board was not the prob lem Continue to look for bad connec tion
60. ONTROL TRANSFORMER T2 VOLTAGE TEST continued ORANGE 12 ORANGE 6 VIEWED FROM END P d PLUG P8 SQUARE WAVE 255 CONTROL FIGURE F 4 CONTROL BOARD AND TRANSFORMER 7 Test the resistance from 8J14 on the protection snubber board to the 432 lead at the control transformer Also check resistance from 4J14 on the pro tection snubber board to the 4433 lead at the control transformer A If zero ohms resistance is shown test is OK 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 Orange to Orange SQUARE WAVE TIG 255 IMPORTANT If the Control Transfor mer is replaced refer to label on the new transformer for correct primary lead connections If connected wrong the machine will have no OCV output If no OCV occurs reverse the control trans former s primary connections and re check machine s OCV Note If main supply voltage varies con trol transformer voltages will vary accordingly Secondary Approximate Lead Colors Voltages Red to Red Red to White Yellow to Yellow Black to Black Blue to Blue LINCOLN TROUBLESHOOTING amp REPAIR F 20 PROTECTION SNUBBER BOARD CONTINUITY TEST A WARNING Service and repair should only be performe
61. R122 R125 R128 R172 R187 R211 R223 R224 R39 R44 R67 R199 R222 R236 R38 R54 R55 R71 R51 R52 R72 R85 R137 R50 R101 R134 R212 R27 R63 R142 R12 R23 R64 R106 R107 R108 R181 R184 R185 R34 R138 R139 R88 R143 R146 R147 R148 R149 R150 R151 R152 R153 R166 R167 R141 R73 R75 R82 R83 R102 R103 R104 R42 R48 R53 R66 R79 R81 R97 R130 R131 R132 R201 R202 R203 R204 R205 R206 R207 R208 R209 R210 R213 R215 R216 R217 R218 R28 R29 R30 R31 R32 R40 R16 R19 R43 R65 R70 R116 R136 R200 CONTROL BOARD G2150 Identification CAPACITOR ALEL 1000 35V 30 20 RESISTOR MF 1 4W 100 1 RESISTOR MF 1 4W 1 00K 1 RESISTOR MF 1 4W 10 0K 1 RESISTOR MF 1 4W 100K 1 RESISTOR MF 1 4W 1 00M RESISTOR MF 1 4W 150 1 RESISTOR MF 1 4W 1 50K 1 RESISTOR MF 1 4W 15 0K 1 RESISTOR MF 1 4W 2 21K 1 RESISTOR MF 1 4W 221K 1 RESISTOR MF 1 4W 267 1 RESISTOR MF 1 4W 2 67K 1 RESISTOR MF 1 4W 26 7 1 RESISTOR MF 1 4W 3 32K 1 RESISTOR MF 1 4W 33 2K 1 RESISTOR MF 1 4W 475 1 RESISTOR MF 1 4W 4 75K 1 RESISTOR MF 1 4W 47 5K 1 RESISTOR MF 1 4W 475K 1 CONT D ON REVERSE PAGE NOTE Lincoln Electric assumes no responsibility for liabilities resulting from board level troubleshooting 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
62. RD THIS DIAGRAM MAY NOT SHOW THE EXACT COMPONENTS OR CIRCUITRY OF CONTROLS HAVING A COMMON CODE NUMBER A MAIN ACL 10 MAIN RECT 2 10 N ARRA GENERAL INFORMATION LAST NO USED ELECTRICAL SYMBOLS PER E1537 CAPACITORS MFD 022 50V UNLESS OTHERWISE SPECIFIED RESISTORS Ohms 1 44 UNLESS OTHERWISE SPECIFIED LABELS DIODES 1A 400V UNLESS OTHERWISE SPECIFIED A SUPPLY VOLTAGE NET ag FROM BRIDGE C 15 918 un CIE y ce ojo TO CONTROL BOARD SCR3 GATE 10 a O POWER SUPPLY SOURCE POINT 5 4 GATE lt 4 10 57 COMMON CONNECTION 7 1 FRAME CONNECTION EARTH GROUND CONNECTION MAIN RECT 1 30 na KLARA SQUARE WAVE TIG 255 SCHEMATIC PROTECTION SNUBBER BOARD Y VERRE YY c i 17201 NOTE Lincoln Electric assumes no responsibility for liabilities resulting from board level troubleshooting PC Board repairs will invalidate your factory warranty This Printed Circuit Board schematic is provided for reference only It may not be totally 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
63. RE WAVE TIG 255 E 5 THEORY OF OPERATION Qio eo AC WELDING OUTPUT 5 9 POLARITY SWITCH p TADS olo AC POSITION o ere WORK HI FREQ TRANSFORMER v ELECTRODE LINE SWITCH MAIN R TRANSFORMER E X2 C T 5 8 e E 5 5 2 a POWER 9 n 5 9 FACTOR dS la CAPACITORS Kk ele 115VAC PROTECTION 115 VAC KEYPAD SNUBBER GATE SIGNALS BOARD m 115 VAC D lt conor 115 TRANSFORMER i RECEPTACLE 20 HIGH VOLTAGE 115 VAC TRANSFORMER HIGH FREQUENCY SPARK REMOTE CIRCUIT RECEPTACLE Qio Ojo By rotating the polarity switch to the AC position the to the other AC side of the bridge The choke is now B 8 welding power circuit is changed One lead X2 of electrically across the negative and positive SCR 9 the main transformer secondary is connected to the bridge connections Due to the ability of the choke to machine s output work stud The other secondary store energy and the SCR s ability to turn on at the lead X1 is connected to one of the AC connections appropriate times an AC Square Wave is developed E 3 on the SCR bridge The electrode stud is connected and applied to the output studs Ww 0 a CHOKE ELECTRODE AG 10 WORK AC WELDING CIRCUIT Return to Section TOC Return to Master TOC LINCOLN 5 SQUARE WAVE TIG 255 Return to
64. S 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 3 4 2 OHMS 3 3 Typical 35 OHMS 32 Typical 1J15 to 1J14 L16 and Board Trace 35 OHMS 32 Typical 1410 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 4011 Board Trace 0 OHMS LINCOLN 5 TABLE F 6 SQUARE WAVE TIG 255 iin TROUBLESHOOTING amp REPAIR ARC START TRIGGER CIRCUIT TEST A WARNING Service and repair should only be performed by 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 Return to Section TOC Return to Master TOC 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 bef
65. S ret Pour Soudage A L Arc 1 Protegez vous contre la secousse lectrique a Les circuits l lectrode et la pi ce sont sous tension quand la machine souder est en marche Eviter toujours tout contact entre les parties sous tension et la peau nue ou les v tements mouill s Porter des gants secs et sans trous pour isoler les mains Faire tr s attention de bien s isoler de la masse quand on soude dans des endroits humides ou sur un plancher metallique ou des grilles metalliques principalement dans les positions assis ou couch pour lesquelles une grande partie du corps peut tre en contact avec la masse Maintenir le porte lectrode la pince de masse le c ble de soudage et la machine souder en bon et s r tat defonctionnement d Ne jamais plonger le porte lectrode dans l eau pour le refroidir Ne jamais toucher simultan ment les parties sous tension des porte lectrodes connect s deux machines soud er parce que la tension entre les deux pinces peut tre le total de la tension vide des deux machines Si on utilise la machine souder comme une source de courant pour soudage semi automatique ces precautions pour le porte lectrode s applicuent aussi au pistolet de soudage 2 Dans le cas de travail au dessus du niveau du sol se pro t ger contre les chutes dans le cas ou on recoit un choc Ne Toujours porter des lunettes de s curit dans la zone de soudage Utiliser des lune
66. SQUARE WAVE TIG 255 For use with machine Code Numbers 10022 10023 10024 10025 10026 10134 Return to Master TOC View Safety Info Safety Depends on You Lincoln arc welding and cutting equipment is designed and built with safety in mind However your overall safety can be increased by proper installation 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 Return to Master TOC View Safety Info Fle Le gc 891 gt 2 gt jag SERVICE MANUAL 2222 Retum to Master TOC View Safety Info LINCOLN amp World s Leader in Welding and Cutting Products Premier Manufacturer of Industrial Motors Sales and Service through Subsidiaries and Distributors Worldwide 22801 St Clair Ave Cleveland Ohio 44117 1199 U S A Tel 216 481 8100 Return to Master TOC Return to Master TOC Q FH 0 5 yp c 3 Retum to Master TOC SAFETY PROTECT YOURSELF AND OTHERS FROM POSSIBLE SERIOUS INJURY OR DEATH KEEP CHILDREN AWAY PACEMAKER WEARERS SHOULD CONSULT WITH THEIR DOCTOR BEFORE OPERATING Read and understand the following safety highlights For additional safety information it is strongly recommended that you pur chase copy
67. Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr un 818 EJE pio oO VU cic E dm mg A L GATE __ Return to Section TOC Return to Master TOC THEORY OF OPERATION E 6 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 In the ON state the SCR acts like a closed switch When the SCR is turned OFF there is no current flow from anode to cathode thus the device acts like an open switch As the name suggests the SCR is a rectifier so it passes current only during positive half cycles of the AC sup ply The positive half cycle is the portion of the sine wave in which the anode of the SCR is more positive than the cathode When an AC supply voltage is applied to the SCR the device spends a certain portion 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 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 than 0 6V Onc
68. TING amp REPAIR F 12 Observe Safety Guidelines TROUBLESHOOTING GUIDE detailed in the beginning of this manual PROBLEMS POSSIBLE AREAS OF RECOMMENDED SYMPTOMS MISADJUSTMENT S COURSE OF ACTION TIG MODE PROBLEMS Machine has low output when in Machine must be in Local Machine controls may be set incor TIG 4 Step Mode Control Mode when 4 Step is rectly used Return to Section TOC Return to Master TOC Contact The Lincoln Electric Service Department 216 383 2531 or 1 800 833 9353 WELD Weak high frequency machine Spark gap may be misadjusted Check for an open or arcing has normal welding output Check and reset per high frequency component maintenance instructions Replace as required Examples R3 R4 C2 Refer Improper shielding gas flow to wiring diagram Adjust for a flow of 10 to 30 CFH 4 7 to 14 1 l min for If spark is weak at the spark most applications gap check or replace high fre quency circuit Examples T3 Work and electrode cables in C3 L3 L4 poor condition allowing high frequency to Leak Off Use good quality cables with a high natural rubber content such as Lincoln Stable Arc Cable Cables should be as short as possible Return to Section TOC Return to Master TOC The display shows zero amps but The arc start switch or amptrol Check Trigger circuit See Arc indicates open circuit voltage may be defective There should approximately 53V The arc start not
69. To change this connection for a different input voltage reconnect the power strap P to the terminal corresponding to the input voltage used Designations on reconnect panel LOW MID and HIGH correspond to the nameplate input voltages of a triple voltage welder Dual voltage welders use only LOW and HIGH Single voltage welders use only HIGH EXAMPLE On a 208 230 460 volt welder LOW is 208V MID is 230V and HIGH is 460V Fuse the input circuit with the recommended super lag fuses or delay type circuit breakers Choose an input and grounding wire size according to local or national codes refer at the beginning of this chapter Using fuses or circuit breakers smaller than recommended may result in nuisance shut offs from welder inrush currents even if not welding at high currents Unbalanced AC TIG welding draws higher input currents than those for stick DC TIG or Balanced AC TIG welding The welder is designed for 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 te Speciicatian baad 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 Also called inverse time or thermal magnetic circuit breakers circuit breakers which have a delay in tripping action that decreases as the magni tude of the
70. arranty For your safety and to avoid Electrical Shock please observe all safety notes and precautions detailed throughout this manual This Troubleshooting Guide is provided to help you locate and repair possible machine malfunctions Simply follow the three step procedure listed below Step 1 LOCATE PROBLEM SYMPTOM Look under the column labeled PROBLEM SYMPTOMS This column describes possible symptoms that the machine may exhibit Find the listing that best describes the symptom that the machine is exhibiting Symptoms are grouped into three main cat egories output problems function prob lems welding problems Step 2 PERFORM EXTERNAL TESTS The second column labeled POSSIBLE AREAS OF MISADJUSTMENT S lists the obvious external possibilities that may con tribute to the machine symptom Perform these tests checks in the order listed In general these tests can be conducted with out removing the case wrap around cover Step 3 PERFORM COMPONENT TESTS The last column labeled Recommended Course of Action lists the most likely com ponents that may have failed in your machine It also specifies the appropriate test procedure to verify that the subject component is either good or bad If there are a number of possible components check the components in the order listed to eliminate one possibility at a time until you locate the cause of your problem All of the referenced test procedures refered to in t
71. as or water flow when The gas or water solenoid may the arc start switch or amptrol is be defective activated in the TIG mode The machine has output and the fan Check for 115vac at the sole runs When toggling between the noid leads The machine must Stick and TIG modes a click be in the TIG mode and the arc CANNOT be heard indicating that start switch activated the solenoids are NOT operating If 115vac is not present at the solenoids then check the Protection Snubber board See Ojo E un 818 EJE plc cic If the above tests are OK Then the Control board may be faulty Replace A CAUTION 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 216 383 2531 or 1 800 833 9353 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC r9 TROUBLESHOOTING amp REPAIR TROUBLESHOOTING GUIDE Observe Safety Guidelines detailed in the beginning of this manual PROBLEMS SYMPTOMS POSSIBLE AREAS OF MISADJUSTMENT S STICK WELDING PROBLEMS RECOMMENDED COURSE OF ACTION Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr un 818 EJE VU cic Return to Section TOC Return to Master TOC Stick e
72. ated on the case front As the Afterflow time is adjusted the Afterflow time in seconds is shown in the Momentary Display SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr s un 818 EJE pio oO VU cic Return to Section TOC Return to Master TOC OPERATION 7 CONTROL PANEL The display is divided into five sections See Figures B 2 a and B 2 b FIGURE B 2 a DISPLAY B ummmm ummmm ummmm Spoor 28888 OC 28889 EEEEH COCO DELE EEEEH Spoor EEEEH 28888 EEEEH CODE 28888 28889 nummum numm cxx nummum o A AC DC INDICATOR B VOLTMETER C AMMETER D MOMENTARY DISPLAY E BAR GRAPH FIGURE B 2 b DISPLAY TE Hs 15 oo a H m on ur 9090 0000000000000000 A AC DC INDICATOR This symbol represents the output polarity of the 255 either
73. aulty 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 Return to Section TOC Return to Master TOC Ojo E un 818 EJE cic A CAUTION 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 216 383 2531 or 1 800 833 9353 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC TROUBLESHOOTING amp REPAIR TROUBLESHOOTING GUIDE Observe Safety Guidelines detailed in the beginning of this manual PROBLEMS POSSIBLE AREAS OF RECOMMENDED SYMPTOMS MISADJUSTMENT S COURSE OF ACTION FUNCTION PROBLEMS The yellow light PL1 on the front Normal condition this light panel is not lit will glow only if machine is in an overheated condition Thermal overload Return to Section TOC Return to Master TOC One or more keypad lights LEDS Be sure that the proper weld Check the Keypad LED board are dark and cannot be lit when mode is selected For to the Control board harness their respective keys are pressed example the high frequency The plugs may be loose or machine is operable keys and keypad lights defective LEDS are not active in the stick mode If on
74. be any continuity between switch or amptrol is not actuated pins D and E on the arc start 2 Control board may be faulty cable connector unless the Replace FH c Uu o Eu unit is actuated 4 Q O FH 0 Ew c lad If an amptrol is not being used the machine must be in the Local Control Mode A CAUTION 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 216 383 2531 or 1 800 833 9353 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Plg TROUBLESHOOTING amp REPAIR TROUBLESHOOTING GUIDE Observe Safety Guidelines detailed in the beginning of this manual PROBLEMS SYMPTOMS POSSIBLE AREAS OF MISADJUSTMENT S TIG WELDING PROBLEMS Torch may be faulty RECOMMENDED COURSE OF ACTION High frequency Spark is present at tungsten electrode but operator is unable to establish a welding arc Machine has normal open circuit voltage approximately 53V Return to Section TOC Return to Master TOC This may be a welding procedure problem If an amptrol is not being used then the machine must be in the Local Control Mode Contact The Lincoln Electric Service Department 216 383 2531 or 1 800 833 9353 WELD Tungsten el
75. beginning of this manual PROBLEMS POSSIBLE AREAS OF RECOMMENDED SYMPTOMS MISADJUSTMENT S COURSE OF ACTION FUNCTION PROBLEMS The control panel displays cannot None Check for loose connections at be read The characters run dis plug J3 on the control board play only half characters or ran dom dots may appear on display The display may be faulty Replace The control board may be faulty Replace The voltmeter always reads 00 None Check the continuity of leads The machine output is normal 305 and 313C and their con nections to the machine output studs Refer to wiring diagram 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 If open circuit voltage is not present at 5J6 and 12J6 see Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC The control panel display back None Check for loose connector ground is dark instead of red The at the Control board machine operates normally The Control board may be faulty Disconnect P3 from the Control board Check voltage from 1J3 to 2J3 on the board See Figure F 1 The voltage should be 15 to 20vdc If the voltage is not correct then replace the Control board Ojo E un 818 EJE plc cic If the Control board is good then the Displa
76. c assumes no responsibility for liabilities resulting from board level troubleshooting 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 could result in damage to the machine SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC LINCOLN Z NOTES SQUARE WAVE TIG 255 G 8 DOL 5 W 03 5 W 03 DOL 5 W 03 5 W 03 DOL U0ON28S DOL uon2es 301 uon2es WNJPY 301 2 5 ELECTRICAL DIAGRAMS G 9 CONNECTED HIGHEST VOLTAGE 150A 400V lof D eio olo WIRING DIAGRAM SQUARE WAVE TIG 255 olg lu oio TO GROUND PER NATIONAL ELECTRIC CODE Un SEE LABEL ON TRANSFORMER en 4 INPUT SUPPLY LINES lt lt lt lt CONNECT THESE TWO LEADS AS 2 o 1 N m SE M 522 ROH pe S 5 S NEEDED FOR CORRECT OPERATION TRIPLE VOLTAGE MACHINE pum 123 PIEZO BUZZER TOROID L
77. ctrode reel welding head nozzle or semiautomatic welding gun are also electrically hot 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 Ground the work or metal to be welded to a good electrical earth ground Maintain the electrode holder work clamp welding cable and welding machine in good safe operating condition Replace damaged insulation Never dip the electrode in water for cooling Never simultaneously touch electrically hot parts of electrode holders connected to two welders because voltage between the two can be the total of the open circuit voltage of both welders When working above floor level use a safety belt to protect yourself from a fall should you get a shock Also see Items 4 c and 6 SQUARE WAVE TIG 255 2 b ARC RAYS can burn 2 a Use a shield with the proper filter and cover 2 plates to protect your eyes from sparks and ag the rays of the arc when welding or observing open arc welding Headshield and filter lens should conform to ANSI 287 standards Use suitable clothing made from durable flame resistant material to protect your skin and that of your helpers from the arc rays Protect other nearby personnel with suitable non flammable screening and or warn them not to watch the arc nor expose themselves to the arc rays or to hot spatt
78. d The 115vac also powers the high voltage circuit The secondary voltages that are developed in the control transformer power the control board On 50 60 Hz machines the main transformer also has a 220vac auxiliary winding that provides power to the 220vac receptacle This 220vac winding is not isolated from the 115vac winding LINCOLN Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr un gis EJE gt pio cic Return to Section TOC Return to Master TOC THEORY OF OPERATION E 2 OUTPUT RECTIFICATION AND FEEDBACK CONTROL POLARITY SWITCH x2 une SWITCH MAIN TRANSFORMER DC SCR BRIDGE 2 ao 1 2 POWER 9 FACTOR CAPACITORS 9 ARC START 115 VAC 115VAC PROTECTION SNUBBER 115 VAC o lt Z CONTROL 115 VAC TRANSFORMER RECEPTACLE ODO 115 VAC REMOTE RECEPTACLE 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 keypad or remote control with the shunt feedback signal The appropriate gate firing pulses are generated by LINCOLN 5 GATE SIGNALS HI FREQ BY PASS BOARD WORK HI FREQ TRANSFORMER ELECTRODE O STOOD E
79. d by 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 Return to Section TOC Return to Master TOC 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 216 383 2531 or 1 800 833 9353 WELD CAUTION If machine case sides and top removed the case back front must be support ed Failure to do this could result in mechanical or electrical damage to the TIG 255 Return to Section TOC Return to Master TOC TEST DESCRIPTION Many circuits pass through the protection snubber board The purpose of this test is to determine if the board s circuitry and components are intact and capable of passing signal currents MATERIALS NEEDED Ohmmeter Multimeter TIG 255 Wiring Diagrams see Electrical Diagram section of manual Protection snubber board Continuity Table Figure F 6 Ojo Fr B un 818 EJE pI P cic Return to Section TOC Return to Master TOC SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Ma
80. e 75 C Copper Ground Input Super Lag Ampere Copper Wire in Wire in Conduit Copper Wire in Wire in Conduit Voltage or Breaker Rating on Conduit AWG AWG IEC Conduit AWG AWG IEC Frequency Nameplate IEC Sizes IEC Sizes Sizes 208 60 230 60 74 6 16mm 8 10mm 37 10 6mm 10 6mm 30 10 6mm 400 50 60 415 50 60 440 50 60 500 50 60 19 0 in Lift bail add 3 5 in 300 Ibs 137 kg 485 mm Lift bail add 90 mm 1 Unbalanced TIG welding above 180 amps will draw higher input currents see Supply Connections section LINCOLN 5 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo E El un 818 EJE VU cic Return to Section TOC Return to Master TOC INSTALLATION 2 Read entire installation section before starting installation SAFETY PRECAUTIONS A WARNING ELECTRIC SHOCK can kill Only qualified personnel should perform this installation Turn the input power OFF at the disconnect switch or fuse box before working on this equipment 0 Do not touch electrically hot parts Always connect the Square Wave TIG 255 grounding terminal located on the bottom of the input connection box to a good electrical earth ground SELECT SUITABLE LOCATION Place the welder where clean cooling air can freely circulate in through the rear louvers and out through
81. e connection sur faces are clean and free from any dirt or paint LINCOLN Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr un 818 EJE pio cic Return to Section TOC Return to Master TOC TROUBLESHOOTING amp REPAIR F 44 RETEST AFTER REPAIR LINCOLN 5 Should a machine under test be rejected for NOTE 50 Hz machines may be tested any reason requiring the removal of any using 60 Hz power 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 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 raptar 447 473 VAC Capacitors OPEN CIRCUIT VOLTAGES 69 73 69 73 VDC 46 54 46 54 VDC Stick Mode OCV TIG Mode OCV MAXIMUM ACCEPTABLE OUTPUT VOLTAGE AT MINIMUM OUTPUT SETTINGS TIG Modes 5 Amps 12 Volts MINIMUM ACCEPTABLE OUTPUT VOLTAGE AT MAXIMUM OUTPUT SETTINGS TIG Modes 255 Amps 29 Volts RECOMMENDED METERS FOR MACHINE OUTPUT TESTS VOLTMETER AC and DC True RMS Meter Fluke 8922A or equivalent AMMETER Columbia Type AX AC or DC Tong Ammeter IMPORTANT IF OTHER TYPE METERS ARE USED RESULTS MAY NOT BE ACCURATE 11 94 SQUARE WAVE TIG 255 ae TROUBLESHOOTING amp REPAIR RETEST A
82. e the SCR has fired it is not necessary to continue the flow of gate current As long as current continues to flow from anode to cathode the SCR will remain on When the anode to cathode current drops below a minimum value called holding current the SCR will shut off This normally occurs as the AC supply volt age passes through zero into the negative portion of the sine wave If the SCR is turned on early in the positive half cycle the conduction time is longer resulting in greater SCR output If the gate firing occurs later in the cycle the conduction time is less resulting in lower SCR output LATER IN THE CYCLE CATHODE TPUT om NOTE AS THE GATE ANODE 5 PULSE IS APPLIED THE SCR OUTPUT IS DECREASED SCR OPERATION LINCOLN 5 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC OJo EJE El un 818 EJE oO VU cic Return to Section TOC Return to Master TOC E 7 THEORY OF OPERATION THERMAL PROTECTION A thermostat protects the machine from excessive operating temperatures Excessive operating temper atures may be caused by a lack of cooling air or oper ating the machine beyond the duty cycle and output rating If excessive operating temperature should occur the thermostat will prevent output voltage or current and the yellow indicator light will glow Additionally the display and ke
83. 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 SQUARE WAVE TIG 255 LINCOLN TROUBLESHOOTING amp REPAIR F 16 PC BOARD CONNECTOR LOCATIONS 2J3 1J3 13J6 12J6 Return to Section TOC Return to Master TOC J2 J3 G2150 5 T o n Eus i d Return to Master TOC SQUARE WAVE 255 CONTROL FIGURE F 1 CONTROL BOARD CONNECTORS Ojo RIR i 09 9 914 1J10 1J11 1J12 1J13 1J14 1J15 g 8 EIE 5 B PROTECTION SNUBBER 919 19255 J10 J11 J12 13 14 15 12 10 10J11 14912 16J13 8J14 6J15 FIGURE F 2 PROTECTION SNUBBER BOARD CONNECTORS Return to Section TOC Return to Master TOC SQUARE WAVE TIG 255 ae TROUBLESHOOTING amp REPAIR CONTROL TRANSFORMER T2 VOLTAGE TEST A WARNI
84. ectrode may be too large for the process If helium shielding gas is being used then reduce percentage of helium If TIG welding in the DC negative mode then a properly sharpened thoriated tungsten should be used Return to Section TOC Return to Master TOC Check the welding cables and output stud connections No high frequency Machine is in the TIG Mode and has normal output In order for the high frequency to operate the machine must be either in the start only Mode or the continuous high Check the high voltage trans former T3 The normal resis tance of the secondary winding of the high voltage transformer frequency mode is 12 5k ohms 115vac is applied to the primary of T3 A very high voltage is developed on the secondary winding For assistance call The Lincoln Electric Service Department 216 383 2531 or 1 800 833 9353 WELD The high frequency spark gap may be too large or shorted Check gap as per maintenance instructions Ojo E El un 818 EJE VU cic Check the values of R3 R4 and C2 Replace if faulty The Protection Snubber board may be faulty See Protection Snubber Board Continuity Test The Control board may be faulty Replace A CAUTION 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 troubleshoot
85. ematic is provided for reference only It may not be totally 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 LINCOLN amp SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC
86. ems such as TIG torches hoses and water coolers OPERATIONAL FEATURES AND CONTROLS The Square Wave TIG 255 has the following controls as standard TIG 2 Step TIG 4 Step Stick mode selec tion Local Remote current control selection Continuous Start Only Off high frequency selection Auto Manual AC wave balance selection with the manual wave balance adjustment TIG pulser On Off selection with frequency adjustment afterflow adjust ment and DC DC AC polarity selection DESIGN FEATURES AND ADVANTAGES Designed to NEMA EW 1 amp International IEC 974 Standards Single output range of 5 315 amps covers the majority of all TIG welding applications Solid State Output Contactor no noise no parts to wear Digital Ammeter and Voltmeter for precise readings from 5 to 315 amps welding LINCOLN 5 B 4 Welding current limit can be preset from 5 to 315 amps and is displayed on the Ammeter when not welding Auto Balance circuitry automatically provides the proper amount of cleaning and penetration when AC TIG welding Manual AC wave balance adjust ment is also possible 2 Step 4 Step Arc Start Switch Capability TIG Pulser with On Off Selection and Pulses Per Second adjustment Background current and duty cycle are automatically adjusted according to the peak welding current Fixed preflow time of 0 5 seconds Preflow time is eliminated if welding restarts during gas afterflow of previous weld This avoids unneces
87. epairs safely contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed call 216 383 2531 or 1 800 833 9353 LINCOLN P 12 95 SQUARE WAVE TIG 255 F 5 TROUBLESHOOTING amp REPAIR TROUBLESHOOTING GUIDE Observe Safety Guidelines detailed in the beginning of this manual PROBLEMS POSSIBLE AREAS OF RECOMMENDED SYMPTOMS MISADJUSTMENT S COURSE OF ACTION OUTPUT PROBLEMS 115VAC Receptacle not working Check for 115VAC at If voltage at the receptacle is properly voltage is below 108VAC receptacle if low below zero then check for open cir Machine has welding output fan is 108VAC then check input cuit breaker CB1 running voltage to machine Return to Section TOC Return to Master TOC Check leads 230 231 and 232 for loose or broken con nections Refer to wiring dia gram Machine regularly overheats ther Welding application may Check for proper fan operation mostat opens PL1 yellow light on exceed recommended duty front panel glows The fan runs cycle The thermostat may be faulty but machine has no output and no Should be normally closed display Dirt and dust may have clogged the cooling channels inside the machine Blow out unit with clean dry compressed air Return to Section TOC Return to Master TOC Air intake and exhaust louvers may be blocked due to inadequate clearance around machine Machine makes a very loud Inspect o
88. epresents 2 mil liseconds in time Trigger Coupling Note Scope probes connected at machine output studs probe to electrode probe to work Return to Section TOC Return to Master TOC LINCOLN 5 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo E El un 818 EJE plc cic Return to Section TOC Return to Master TOC LINCOLN 5 TROUBLESHOOTING amp REPAIR FAN MOTOR AND BLADE REMOVAL A WARNING Service and repair should only be performed by 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 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 A CAUTION 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 electrical damage to the TIG 255 TEST DESCRIPTION The following procedure will aid the technician in gaining access to the fan blade and
89. er or metal 23 FUMES AND GASES can be dangerous 3 a Welding may produce fumes and gases hazardous to health Avoid breathing these fumes and gases When welding keep your head out of the fume Use enough ventilation and or exhaust at the arc to keep fumes and gases away from the breathing zone When welding with electrodes which require special ventilation such as stainless or hard facing see instructions on container or MSDS or on lead or cadmium plated steel and other metals or coatings which produce highly toxic fumes keep exposure as low as possible and below Threshold Limit Values TLV using local exhaust or mechanical ventilation In confined spaces or in some circumstances outdoors a respirator may be required Additional precautions are also required when welding on galvanized steel Do not weld in locations near chlorinated hydrocarbon vapors coming from degreasing cleaning or spraying operations The heat and rays of the arc can react with solvent vapors to form phosgene a highly toxic gas and other irritating products Shielding gases used for arc welding can displace air and cause injury or death Always use enough ventilation especially in confined areas to insure breathing air is safe Read and understand the manufacturer s instructions for this equipment and the consumables to be used including the material safety data sheet MSDS and follow your employer s safety practices MSDS forms are ava
90. gs B 6 Control Panel 6 Case Front Gontrols 7 Hand and Foot Amptrol Operation B 8 Welding Operation is B 8 B 11 TIG Welding Guidelines ss B 8 5 TIG Welding Sequence of Operation 2 Step B 9 5 TIG Welding Sequence of Operation 4 Step B 10 Advanced Tig Welding Features B 11 Auxillary 11 Overload Protection iii B 12 E Q FH 0 5 Ew c Retum to Master TOC LINCOLN E SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo E El un 818 EJE plc cic Return to Section TOC Return to Master TOC SQUARE WAVE TIG 255 OPERATION OPERATING INSTRUCTIONS Read and understand entire section before operating machine GENERAL WARNINGS SAFETY PRECAUTIONS WARNING ELECTRIC SHOCK can kill Do not touch electrically live parts or electrode with skin or wet clothing Insulate yourself from work and ground Always wear dry insulating gloves FUMES AND GASES can be dangerous Keep your head out of fumes E I Use ventilation or exhaust to remove fumes from breathing zone WELDING SPARKS can cause fire or explosion I
91. h Depressing the Amptrol just past minimum will cause the Amptrols built in arc start switch to close and backing off completely causes the built in start switch to open The Amptrol will have no effect on the welding current when used as an arc start switch LINCOLN 5 WELDING OPERATION TIG WELDING Familiarize yourself with the Controls and Display Section before attempting operation of the Square Wave TIG 255 TIG WELDING GUIDELINES TIG welding can be done in either the TIG 2 Step or the TIG 4 Step Weld Mode TIG 2 Step is typically used with Hand or Foot Amptrols with Remote Current control TIG 4 Step is typically used with Arc Start switches and Local Current Control because it provides a very brief current upslope and a 5 second current downslope TIG 4 Step also functions like a trigger interlock making it unnecessary to hold down the Arc Start switch during a weld Read the TIG Welding Sequence of Operation sections for more details on 2 Step and 4 Step Operation Refer to Table B 2 for guidelines on electrode sizes torch nozzles and shielding gas flow rates TABLE B 1 RECOMMENDED POLARITY SETTINGS FOR TIG WELDING Electrode High Frequency Setting Type of Welding Polarity Stainless Steel Aluminum amp Magnesium CONTINUOUS Other Metals DC START SQUARE WAVE TIG 255 ET OPERATION TABLE B 2 oio 2 TYPICAL CURRENT RANGES FOR TUNGSTEN ELECTRODES 5 5 Approximate Argon 0
92. he Troubleshooting Guide are 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 CAUTION 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 216 383 2531 or 1 800 833 9353 CAUTION If machine case sides and top are removed the case back and front must be sup ported Failure to do this could result in mechanical or electrical damage to the TIG 255 This is best accomplished with a wooden block Refer to Figure F 3 as an example CAUTION HIGH VOLTAGE HIGH FREQUENCY can damage test equipment Perform all voltage and waveform checks with high frequency circuit OFF SQUARE WAVE TIG 255 LINCOLN Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr un 818 EJE pio oO VU cic Return to Section TOC Return to Master TOC LINCOLN 5 TROUBLESHOOTING amp REPAIR F 2 PC BOARD TROUBLESHOOTING PROCEDURES A WARNING ELECTRIC SH
93. hooting PC Board repairs will invalidate your factory warranty This Printed Circuit Board schematic is provided for reference only It may not be totally 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 LINCOLN SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Q o 5 4 nn 2 4 2 7 ac Return to Section TOC Return to Master TOC hz wn o o 2 D ELECTRICAL DIAGRAMS G 12 CONTROL BOARD SCHEMATIC SQUARE WAVE TIG 255 cont d G2150 475 0011 KEYPAD 013 T 600mA gore 40V 014 J2 600mA 1 40V TK Q AC DC MICROSWITCH 40V 475 an D 600mA R172 5 L 5V
94. ign and may result in Danger to the Machine Operator or Technician Improper PC board repairs could result in damage to the machine LINCOLN jo SQUARE WAVE TIG 255 ELECTRICAL DIAGRAMS G 13 PROTECTION SNUBBER BOARD SCHEMATIC SQUARE WAVE TIG 255 L9255 ELECTRODE STUD lt s B CY NY CY ELECTRODE STLD 2 WORK STUD lt 3H AA WORK STUD a eu AC DC AC DC MICRO SWITCH 0047 MICRO SWITCH Lo 5 J3 POT HI 2 POT HI Por WIPER B NN POT WIPER 17 BOT Lo rr POT LO 93 REMOTE el REMOTE ASS T 0057 ASS 3000V lt 3 lt J13 Return to Section TOC Return to Master TOC TO CONTROL BOARD FROM MACHINE 0047 RANSF ORMER 115 VAC 1 4 lt J15 s J15 HIGH VOLTAGE TRANSFORMER 45 lt J5 SYN MAIN XFMR c29 sae T Return to Section TOC Return to Master TOC lt 2 15 B EET d ar 15 GAS SOLENOID lt lt ore e e 1 65 WATER SOLENOID UNUSED PINS SCRI GATE lt 9 c CHASSIS SCR2 GATE a 7 amp MAIN i9 7 m SINCE COMPONENTS OR CIRCUITRY ON PRINTED CIRCUIT BOARD MAY CHANGE WITHOUT AFFECTING THE INTERCHANGEABILITY OF A COMPLETE BOA
95. ilable from your welding distributor or from the manufacturer Also see item 7b LINCOLN Return to Master TOC Return to Master TOC Q O FH 0 4 5 4 c 3 Retum to Master TOC SAFETY 7 WELDING SPARKS gt cause fire or explosion 4 a Remove fire hazards from the welding area If this is not possible cover them to prevent the welding sparks from starting 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 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 and the operating information for the equipment being used When not welding make certain no part of the electrode circuit is touching the work or ground Accidental contact can cause overheating and create a fire hazard Do not heat cut or weld tanks drums or containers until the proper steps have been taken to insure that such procedures will not cause flammable or toxic vapors from substances inside They can cause an explosion even though they have been cleaned For information purchase Recommended Safe Practices for the Preparation for Welding and Cutting of Containers and Piping That Have
96. ill represent the Momentary Display value not the ammeter value CASE FRONT 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 LOAD FIGURE B 3 CASE FRONT CONTROLS MM gt ace me 00 A FES o cs UU OO m 1 POWER SWITCH 2 THERMOSTATIC PROTECTION LIGHT 3 POLARITY SWITCH LINCOLN Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr un 818 EJE pio oO VU cic Return to Section TOC Return to Master TOC OPERATION 86 HAND AND FOOT AMPTROL ACCESSORY OPERATION Both the Hand and Foot Amptrol work in a similar manner They are meant to be used for remote current control when Remote Current Control is selected The TIG 2 Step mode must be selected when using an Amptrol for remote current control As explained below Amptrols can also be used as arc start switches if Local Current C
97. ing assistance before you proceed call 216 383 2531 or 1 800 833 9353 Return to Section TOC Return to Master TOC LINCOLN SQUARE WAVE TIG 255 TROUBLESHOOTING amp REPAIR F 14 Observe Safety Guidelines TROUBLESHOOTING GUIDE detailed in the beginning of this manual PROBLEMS POSSIBLE AREAS OF RECOMMENDED SYMPTOMS MISADJUSTMENT S COURSE OF ACTION TIG WELDING PROBLEMS No gas or water flow when arc start 1 Gas supply is empty or not Possible gas or water supply switch or amptrol is activated in the turned on problem TIG Mode Machine has output fan runs When toggling between Gas or water hose may be Contact The Lincoln Electric the Stick and TIG Modes a Click pinched Service Department 216 383 can be heard indicating that the 2531 or 1 800 833 9353 WELD solenoids are operating Gas or water solenoid may be blocked with dirt Use filters to prevent reoccurrence Consult your Local welder gas distributor Return to Section TOC Return to Master TOC Arc rectification when AC TIG weld 1 Tungsten electrode may be Check components R3 ing too small for process and C2 in the high voltage transformer primary circuit Manual balance control may Replace if faulty be misadjusted Readjust to the negative direction Check the SCR bridge See and Active SCR Tests Return to Section TOC Return to Master TOC If helium gas is being used reduce percentage of helium There is no g
98. inted 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 result in damage to the machine LINCOLN 5 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC G 7 Oly PROTECTION SNUBBER BOARD L9255 FIR 5 Item Identification 2 i 9 C23 C24 C25 C26 CAPACITOR CEMO 4700P 50V 10 2 J15 CONNECTOR MOLEX MINI PCB 6 PIN 9 9 J14 CONNECTOR MOLEX MINI PCB 8 PIN 5 L1 L2 L3 L4 L5 L6 L7 CHOKE 390UH 5 225MA CONFORMAL a E L8 L9 L10 L11 R1 R2 R3 R4 RESISTOR CC 2W 47 10 J11 CONNECTOR MOLEX MINI PCB 10 PIN J10 CONNECTOR MOLEX MINI PCB 12 PIN J12 CONNECTOR MOLEX MINI PCB 14 PIN J13 CONNECTOR MOLEX MINI PCB 16 PIN C1 C2 C3 C4 C5 C6 CAPACITOR CD 0047 3000V 20 C7 C8 C9 C10 C11 C12 C13 C14 C15 5 C16 C17 C18 C29 C19 C20 C21 C22 CAPACITOR PEF 0 68 400V 10 EET L12 L13 L14 L15 L16 CHOKE RF 390UH 1095 1A SLEEVED D TP1 TP2 TP3 TP4 MOV 150VRMS 45J 14MM gt 5 MOV 320VRMS 160J 20MM 818 C27 C28 0 1 400 10 R5 R6 RESISTOR MF 1 4W 26 7 1 als oO VU ic Ojo Fr un 818 EJE pio oO VU cic NOTE Lincoln Electri
99. ir running current These higher starting currents may cause the circuit breaker to open If this situation occurs the user should refrain from using the Square Wave TIG 255 auxiliary for that equipment 50 60Hz MACHINES Square Wave TIG 255 machines rated for 50 60Hz operation provide 2 amps of 220 volt AC power at a continental European Schuko type receptacle locat ed on the lower case back of the machine 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 LINCOLN OPERATION B 12 CAUTION Note that some types of equipment especially pumps and motors have starting currents which are signifi cantly higher than their running currents These higher starting currents may cause the circuit breaker to open If this situation occurs the user should refrain from using the Square Wave TIG 255 auxiliary for that equipment Return to Section TOC Return to Master TOC 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 Protection Light on the case front see Figure 2 Also the
100. isconnect ed The fan motor may be removed by removing the two 8 32 hex nuts and associated plain and lock washers that mount the motor to the vertical bracket LINCOLN Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr un 818 EJE Bio cic Return to Section TOC Return to Master TOC LINCOLN 5 TROUBLESHOOTING amp REPAIR SCR HEAT SINK ASSEMBLY REMOVAL A WARNING Service and repair should only be performed by 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 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 A CAUTION 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 electrical damage to the TIG 255 TEST DESCRIPTION The following procedure will aid the technician in the removal and replacement of either or both of the two SCR heat sink assemblies MATERIALS REQUIRED
101. it outlined battery if voltage is less than 4 5 volts in Figure F 15 One 6V lantern battery can be used Resistor values are 010 The 1 Connect SCR into the test circuit as voltmeter scale should be low approximate shown A lead to anode C lead to ly 0 5 or 0 10 volts 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 With switch SW 1 closed close switch SW 2 for two seconds and release The voltmeter should read 3 to 6 volts before and after switch SW 2 is released If the voltmeter does not read or reads only while SW 2 is depressed the SCR or battery is defective repeat Battery Test Procedure 4 Open switch SW 1 disconnect the gate lead G and reverse the A and C leads on the SCR Close switch SW 1 The voltmeter should read zero If the voltage is higher than zero the SCR is shorted 12 95 SQUARE WAVE TIG 255 F 31 TROUBLESHOOTING amp REPAIR NORMAL OPEN CIRCUIT VOLTAGE WAVEFORM DC STICK MODE CAUTION HIGH VOLTAGE HIGH FREQUENCY can damage test equipment Perform all voltage and waveform checks with high frequency circuit OFF Return to Section TOC Return to Master TOC CH1 0 volts T o n Eus i d Return to Master TOC 50 volts ams 9 5 wc 918 un
102. lder power supply lines as short as possible and completely enclose them in rigid metallic conduit or equivalent shielding for a minimum distance of 50 feet 15 2m There should be good electrical contact between this conduit and the welder Both ends of the conduit should be connected to a driven ground and the entire length should be continuous 2 Keep the work and electrode leads as short as possible and as close together as possible Lengths should not exceed 25 ft 7 6m Tape the leads together when practical 3 Be sure the torch and work cable rubber coverings are free of cuts and cracks that allow high frequency leakage Cables with high natural rubber content such as Lincoln Stable Arc better resist high frequency leakage than neoprene and other synthetic rubber insulated cables SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr a un 818 EJE pio oO VU cic Return to Section TOC Return to Master TOC A 3 4 Keep the torch in good repair and all connections tight to reduce high frequency leakage 5 The work terminal must be connected to a ground within ten feet of the welder using one of the following methods a A metal underground water pipe in direct contact with the earth for ten feet or more b A 3 4 19mm galvanized pipe or a 5 8 16mm solid galvanized iron steel or copper rod driven
103. lectrode Blasts Off when arc is struck Cannot adjust AC Wave Balance when welding in the Stick Mode Machine welds at a very low output regardless of the preset current set ting arc is stable Variable or sluggish welding arc when welding in the Stick Mode Weld current is set too high for recommended electrode size Reduce preset current adjustment This is a normal condition Wave balance keys are automatically disabled in the Stick Mode If welding in the Remote Control Mode the remote amptrol may be defective or not installed properly If the output is low when the machine is in the Local Control Mode the problem could be internal to the machine Check work and electrode cables for loose or poor connections The weld cables may be too small or too long to permit the desired current to flow The preset current adjustment may be set too low 1 Possible faulty SCR bridge SeelStaticlana Active SCR Tests 2 Control board may be faulty Replace Check the SCR bridge See and Active SCR Tests Check polarity switch S2 connections and operation Check the control transformer T2 See Control Transformer Voltage Test The Control board may be faulty Replace Check polarity switch S2 for wear or loose connentions Check interior connections of the heavy current carrying leads A CAUTION If for any reason you do not understand the test procedures or ar
104. lfunction and overheating of the water cooled torch Connect the torch water line to the welder Water Out fitting Use a nonmetallic drain line from the electrode connection to the drain or water recircu lating pump For other water coolers or torches consult the manu facturer s instructions for the water cooler or TIG torch being used SQUARE WAVE TIG 255 INSTALLATION STICK ELECTRODE CABLE CONNECTION Turn the Power switch Off Run the electrode and work cables through the strain relief holes below the welding output terminals and connect the cables to the proper terminals This strain relief prevents dam age to the welding output terminals if the cables are pulled excessively Select cable size according to Table A 1 A WARNING Do not connect a TIG torch and stick electrode cable at the same time They will both be electrically HOT whenever the output contactor is energized LINCOLN TABLE OF CONTENTS Section B 9 OPERATION SECTION g gt 8 ODE D te tim Comi Coppa read Section B Safety Precautions 1 U Graphic Symbols attente B 2 B 3 General Description eese tnter tnn tnter nnns B 4 Design Features and Advantages B 4 Welding Capability iii 5 5 Controls and Settin
105. ll other moving parts when starting operating or repairing equipment 8 d 4 Connect the work cable to the workpiece as close as possible to the area being welded 8 d 5 Do not work next to welding power source Mar 93 7 6 In some cases it may be necessary to remove safety guards to perform required maintenance Remove guards only when necessary and replace them when the maintenance requiring their removal is complete Always use the greatest care when working near moving parts Do not put your hands near the engine fan Do not attempt to override the governor or idler by pushing on the throttle control rods while the engine is running Q FH 0 5 yp c prevent accidentally starting gasoline engines while turning the engine or welding generator during maintenance work disconnect the spark plug wires distributor cap or magneto wire as appropriate 7 h To avoid scalding do not remove the radiator pressure cap when the engine is hot Retum to Master TOC LINCOLN SQUARE WAVE TIG 255 Return to Master TOC Return to Master TOC Q O 0 4 5 4 c E a Retum to Master TOC SAFETY PRECAUTIONS DE SURETE Pour votre propre protection lire et observer toutes les instruc tions et les pr cautions de s ret specifiques qui parraissent dans ce manuel aussi bien que les pr cautions de s ret g n rales suivantes
106. localized Electric and Magnetic Fields EMF Welding current creates EMF fields around welding cables and 7 b Operate engines in open well ventilated welding machines areas or vent the engine exhaust fumes 40 outdoors 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 Return to Master TOC EMF fields may interfere with some pacemakers and welders having a pacemaker should consult their physician before welding Exposure to EMF fields in welding may have other health effects which are now not known All welders should use the following procedures in order to 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 minimize exposure to EMF fields from the welding circuit 8 d 1 Route the electrode and work cables together Secure them with tape when possible 8 d 2 Never coil the electrode lead around your body 8 d 3 Do not place your body between the electrode and work cables If the electrode cable is on your right side the work cable should also be on your right side Return to Master TOC Keep all equipment safety guards covers and devices in position and in good repair Keep hands hair clothing and tools away from V belts gears fans and a
107. ly E1 E 5 SCR Operalioh enter tere alate fad eet ei atest E 6 Thermal Protection raise detecte oa tese scc ia E ed E 7 Troubleshooting and Repair Section F How To Use Troubleshooting Guide F 1 PC Board Troubleshooting Procedures ssseessseessseessreesisssiissriresinnssrnsssrnssennens F 2 Troubleshooting Guide ssssssssssseeeeeeneren nennen F 3 F 15 Test Procedures iet teret eret ee erue F 17 F 28 Oscilloscope 31 39 Replacement 40 42 Re Test After Repair ss 44 Electrical Section G Parts Manual P 241 LINCOLN 5 SQUARE WAVE TIG 255 TABLE OF CONTENTS Section A e INSTALLATION SECTION H 8 2 RENO FA PR O aS M CI E cR dt d CD d Section A E Technical led a ne le ane tan A 1 m m Input and Output Specifications E Cable and Fuse Sizes Physical Dimensions OCATIOME Em A 2 SLACKING wc nites a A 2 A 2 High Frequency Interference Protection A 2 Input Connections dues A 3 Reconnect
108. ly one red LED won t light the LED PC Board may be defective Replace If three or more red LEDS do not light the Control board may be faulty Replace Return to Section TOC Return to Master TOC The Beeper Piezoelectric Buzzer Background noise may be too Watch the Control Panel cannot be heard machine operat loud for user to hear beeper Display to see if the keys are ing normally responding properly to key presses If so then the Buzzer may be defective Replace the Piezo Electric Buzzer HINT The Piezo Electric Buzzer may be checked by applying a 9vdc signal to the buzzer leads Red lead to Black lead to The Control board may be faulty Check for the presence of 15vdc at pins 6J6 to 13J6 at the Control board Sed figure at end of this Guide The 15vdc will be present for a very short period of time when a key is pressed If the voltage is not present then replace the Control board Ojo E un 818 EJE 0 cic A CAUTION 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 216 383 2531 or 1 800 833 9353 LINCOLN 5 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC TROUBLESHOOTING amp REPAIR F 8 Observe Safety Guidelines TROUBLESHOOTING GUIDE detailed in the
109. 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 LINCOLN jo SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC ELECTRICAL DIAGRAMS G 14 KEYPAD LED BOARD SQUARE WAVE TIG 255 L9212 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC HF NOISE PROTECTION COPPER GRID NOTES GENERAL INFORMATION LABELS NA SINCE COMPONENTS OR CIRCUITRY ON PRINTED A CIRCUIT BOARD MAY CHANGE WITHOUT AFFECTING ELECTRICAL SYMBOLS PER E1537 THE INTERCHANGEABILITY A COMPLETE BOARD CAPACITORS MFD 022 50V UNLESS OTHERWISE SPECIFIED C 15 918 un CIE y ce ojo SUPPLY VOLTAGE NET 77 FRAME CONNECTION Ls THIS DIAGRAM MAY NOT SHOW THE EXACT COMPONENTS RESISTORS Ohms 1 4W UNLESS OTHERWISE SPECIFIED O POWER SUPPLY SOURCE POINT OR CIRCUITRY OF CONTROLS HAVING A COMMON CODE NUMBER DIODES 1 4001 UNLESS OTHERWISE SPECIFIED V COMMON CONNECTION EARTH GROUND CONNECTION SQUARE WAVE TIG 255 SCHEMATIC KEYPAD LED BOARD S 20881 NOTE Lincoln Electric assumes no responsibility for liabilities resulting from board level troubleshooting PC Board repairs will invalidate your factory warranty This Printed Circuit Board sch
110. nel Display and red LEDS will illuminate when the power is on 3 Select the TIG 2 Step Weld Mode 8 Select TIG Pulser On or Off If the TIG Pulser is on adjust the pulse frequency with the Pulses Per Second Up Down keys See the Advanced Features section for more information on setting and using the TIG Pulser 4 Select Local if using an Arc Start Switch or Remote if using an Amptrol current control Set the output current using the Amps Up Down keys The output current setting will be displayed on the Return to Section TOC Return to Master TOC Ammeter LINCOLN amp SQUARE WAVE 255 12 95 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr a un 818 EJE pio VU cic Return to Section TOC Return to Master TOC OPERATION P 19 9 Set the Afterflow time with the Seconds Up Down keys Afterflow time provides shielding gas flow and cooling water if used after the weld Use short Afterflow times with low currents and small tungstens use long afterflow times at high output currents with large tungstens 10 Press and release the Arc Start Switch and set the gas flow meter The welder is now ready for welding 11 Position the tungsten electrode at the start of the weld at a 65 to 75 angle with the horizontal so that the electrode is approximately 1 8 4mm above the work piece Press the Arc Start Switch This
111. obe to work Return to Section TOC Return to Master TOC LINCOLN 5 SQUARE WAVE TIG 255 TROUBLESHOOTING amp REPAIR F 36 AC TIG MODE AUTO BALANCE ON A CAUTION HIGH VOLTAGE HIGH FREQUENCY can damage test equipment Perform all voltage and waveform checks with high frequency circuit OFF G T o n Return to Master CH1 CH1 oio cate 1 8 0 volts DESP ps 0 volts o 1 15 9 8 HE 5 i 20 volts i 2ms 20 volts 2ms MACHINE LOADED TO 50 AMPS AT 26VAC MACHINE LOADED TO 200 AMPS AT 46 VAC oio e These are typical AC output voltage wave SCOPE SETTINGS forms generated from properly operating 8 m machine Note each vertical division repre 2 sents 20 volts and each horizontal division Volts Div represents 2 milliseconds in time The Horizontal Sweep cele machine was loaded with a resistance grid Bla bank As the load is increased the output Coupling waveform becomes more square Trigger Note Scope probes connected at machine output studs probe to electrode probe to work Return to Section TOC Return to Master TOC SQUARE WAVE TIG 255 F 37 TROUBLESHOOTING amp REPAIR TYPICAL SCR GATE VOLTAGE WAVEFORM
112. of Safety in Welding amp Cutting ANSI Standard 249 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 BE SURE THAT ALL INSTALLATION OPERATION MAINTENANCE AND REPAIR PROCEDURES ARE PER FORMED ONLY BY QUALIFIED INDIVIDUALS ELECTRIC SHOCK can kill 1 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 1 b Insulate yourself from work and ground using dry insulation Make certain the insulation is large enough to cover your full area of physical contact with work and ground In addition to the normal safety precautions if welding must be performed under electrically hazardous conditions in damp locations or while wearing wet clothing on metal structures such as floors gratings or scaffolds when in cramped positions such as sitting kneeling or lying if there is a high risk of unavoidable or accidental contact with the workpiece or ground use the following equipment Semiautomatic DC Constant Voltage Wire Welder DC Manual Stick Welder AC Welder with Reduced Voltage Control In semiautomatic or automatic wire welding the electrode ele
113. ontrol 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 Hand Amptrol The Amptrol is capable of controlling the output current from 5 amps to the preset current displayed on the ammeter For example if the ammeter is preset for 200 amps and the Current Control switch is in the REMOTE position the Amptrol when depressed just past its minimum position will cause the Square Wave TIG 255 to weld at 5 amps At the Amptrols maximum position the output would be near 200 amps It is important to note that for many applications the tungsten will not start an arc at only 5 amps To start an arc reliably it is important to depress the Amptrol far enough so that the machine output current is near the tungsten operating range In the example above a 3 32 tungsten may be used on DC to weld near 200 amps To start the weld the operator may have to depress the Amptrol approximately 1 4 of the way down or to nearly 50 amps in order to start the arc Merely depressing the Amptrol to its 5 amp minimum position will not start the arc If the Current Control switch is set to the LOCAL position an Amptrol can be used as an arc start switc
114. or most welding conditions Auto Balance gives the ideal amount of cleaning and penetration based on the welding current output Manual adjustment of the AC Wave Balance is also possible Select the Manual Balance key and the Balance setting will appear in the Momentary Display Manual Balance settings vary from 5 maximum cleaning to 10 maximum penetration A setting of 0 yields a balanced output equal amounts of cleaning and penetration Use the following as a guide when setting the Balance manually BALANCED 0 The amounts of positive and negative are the same CLEANING 1 to 5 Provides more positive current than negative Since the positive current produces the cleaning or oxide removal on aluminum this setting is used for welding on heavily oxidized aluminum PENETRATION 1 to 10 Provides more negative current than positive The arc plasma will be more concentrated and more easily directed to where the heat is needed Higher penetration settings allow a given size of tungsten to carry more current CAUTION Use only the amount of cleaning required because the greater amount of positive current will heat the tungsten more and possibly cause it to melt or spit Also the arc is usually more flared and less stable with more cleaning current In general use just enough cleaning to remove oxides and to give good wetting to the puddle TIG PULSER The Square Wave TIG 255 contains a unique TIG
115. ore you proceed call 216 383 2531 or 1 800 833 9353 WELD CAUTION If machine case sides top removed the case back and front must support ed Failure to do this could result in mechanical or electrical damage to the TIG 255 Return to Section TOC Return to Master TOC TEST DESCRIPTION The Arc Start Trigger Test determines if the wiring and connections are good from the six pin amphenol receptacle to the protection snubber board and also from the protec tion snubber board to the control board MATERIALS NEEDED Ohmmeter Multimeter TIG 255 Wiring Diagrams see Electrical Diagrams section of this manual Arc Start Trigger Circuit Figure F 10 Ojo Fr un 818 EJE pio cic Return to Section TOC Return to Master TOC LINCOLN 5 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr un 818 EJE pio oO VU cic Return to Section TOC Return to Master TOC LINCOLN 5 1 2 TROUBLESHOOTING amp REPAIR F 24 CONTROL BOX CONTROL BOARD LOCATED INSIDE PROTECTION SNUBBER BOARD LOCATED ON BACK OF CONTROL BOX ARC START TRIGGER CIRCUIT TEST continued SUPORT CASE BACK AND CENTER BAFFLE WITH WOOD 2 X 4 FIGURE F 7 LOCATION OF PROTECTION SNUBBER BOARD TEST PROCEDURE Remove main supply power to machine Remove plug 6 from the con
116. otection Snubber board J10 and J11 See Figure F 2 at end of this Guide for location The voltmeter reads 00 in Stick Mode and there is no output from the machine when in the TIG 2 Step Mode Check the wiring to the Control Transformer T2 Observe directions on decal The Protection Snubber board may be faulty See Protection Snubber Board Continuity Test Check the Control Transformer T2 See Control Transformer Voltage Test Check the polarity switch S2 for loose or broken connections 6 Checkthe SCR bridge See and Active SCR Tests If all previous tests are OK then replace the Control board Check trigger circuit See Ard Start Trigger Circuit Test Check the Control transformer Machine MUST be in one of the TIG Modes Machine does not respond no gas flow no high frequency and no open circuit voltage when arc switch or amptrol is activated displays and fan working Note Machine may have OCV in the Stick Mode The arc start switch or amptrol may be defective Check for continuity between pins D and E on cable connector when arc switch or amptrol is activated T2 See Control Transforme Voltage Test Protection Snubber board may be faulty See Protection Snubber Board Continuity Test If all previous tests are OK then replace the Control board A CAUTION If for any reason you do not understand the test procedures or are unable to perform the tests r
117. rk gap generator and also to the high frequency transformer The high fre quency transformer transfers the high frequency spark to the electrode stud LINCOLN 5 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo Fr un gis EJE Bio cic Return to Section TOC Return to Master TOC THEORY OF OPERATION E 4 DC WELDING OUTPUT jog VS WORK O HI FREQ TRANSFORMER ELECTRODE LINE SWITCH MAIN R TRANSFORMER C C T 5 05 E 5 2 POWER FACTOR us CAPACITORS 9 115VAC PROTECTION ___5 CONTROL KEYPAD SNUBBER GATE SIGNALS gt LED HI FREQ lt Der 115 VAC Q CONTROL 24 115 VAC TRANSFORMER RECEPTACLE ea HIGH VOLTAGE 115 VAC TRANSFORMER HIGH FREQUENCY SPARK REMOTE CIRCUIT RECEPTACLE When the polarity switch is placed in either DC posi trolled DC output Since the choke is in series with tion the AC voltage from the main transformer sec the negative leg of the bridge and also in series with ondary is applied to the SCR bridge The SCR bridge the welding load a filtered DC is applied to the and choke circuits are connected in a conventional full machine s output studs wave bridge and filter configuration resulting in a con CHOKE ELECTRODE O NN PRIMARY DC 10 WORK DC WELDING CIRCUIT SQUA
118. roubleshooting 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 could result in damage to the machine LINCOLN 5 SQUARE WAVE TIG 255 D 5 N o gt a lt 5 E 2 m 5 l DOL 03 DOL 5 03 DOL 5 W 03 5 W 03 WIN d 301 uon2es DOL uon2es WNJPY 301 uon2es WNJPY 301 uon2es G 6 PROTECTION SNUBBER BOARD L9255 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC s 1 889061 H388hINS NOIL9310Hd OJo EJE El un 818 EJE oO VU cic NOTE Lincoln Electric assumes no responsibility for liabilities resulting from board level troubleshooting PC Board repairs will invalidate your factory warranty Individual Pr
119. s are used to set thewelding cur rent from 5 to 315 amps as well as to select Local or Remote control Local control allows the current to be adjusted only with the Amps Up Amps Down keys Remote control allows the use of a hand or foot operated remote control Read the complete Operating Instructions section for more information on Local and Remote HIGH FREQUENCY These keys are active in the TIG mode only Select from Continuous Start Only or Off Read the TIG Welding Section for information on High Frequency LINCOLN 5 the AC TIG mode only They are used to set the amount of cleaning and or penetration produced during an AC TIG weld Auto Balance automatically sets the AC Wave Balance according to the welding current If manual adjustment is desired the Manual Balance key can be pressed and the balance adjusted from 5 cleaning to 10 penetration with the Cleaning and Penetration keys Read the Advanced Features section for a complete explanation of the AC Wave Balance TIG PULSER These keys are active in the TIG mode only The On Off keys turn the TIG Pulser on and off The Pulses Per Second keys adjust the pulsing frequency up and down from 0 5 to 10 pulses per second Read the Advanced Features section for more information on the TIG Pulser AFTERFLOW These keys are active in the TIG mode only They must adjust the afterflow time from 5 to 50 seconds for shielding gas and cooling water flow through solenoids loc
120. s in the control wiring harness junction blocks and terminal strips b If the original problem is recreated by the substitution of the original board then the PC board was the problem Reinstall the replacement PC board and test the machine 6 Always indicate that this procedure was followed when warranty reports are to be submitted NOTE Following this procedure and writ ing on the warranty report INSTALLED AND SWITCHED PC BOARDS TO VERIFY PROBLEM will help avoid denial of legiti mate PC board warranty claims SQUARE WAVE TIG 255 F3 TROUBLESHOOTING amp REPAIR TROUBLESHOOTING GUIDE Observe Safety Guidelines detailed in the beginning of this manual PROBLEMS POSSIBLE AREAS OF RECOMMENDED SYMPTOMS MISADJUSTMENT S COURSE OF ACTION OUTPUT PROBLEMS Major Physical or Electrical Contact The Lincoln Electric Damage is Evident Service Dept 216 383 2531 or 1 800 833 9353 WELD Return to Section TOC Return to Master TOC Machine is Dead Make certain that the input Check input power switch S1 No Output No Fan power switch is in the ON It may be faulty No Displays position Check for open or broken pri Check the input voltage at the mary leads to main transformer machine Input voltage must T1 match the rating plate and reconnect the panel Check auxiliary 115vac power winding in the main transformer Blown or missing fuses in T1 input line Return to Section TOC Return to Mas
121. sary delays when making repeated welds Adjustable afterflow time control Local Remote current selection Stick TIG selection Continuous Start Off High Frequency selection DC AC DC Polarity Switch Power Factor Correction for lower input currents and smaller input wire sizes Remote Receptacle for Amptrol or Arc Start Switch Low Voltage Arc Start Switch Circuit 24 V AC for maximum operator safety Gas and optional Water Valves Inlet amp outlet fittings conform to Compressed Gas Association CGA standards Built in High Frequency Generator 115 Volt Receptacle with 10 amp Circuit Breaker 220 Volt European Schuko type receptacle with 2 amp circuit breaker for water coolers 50 60Hz machines only Excellent arc starting and stability up through 315 amps High resistance to AC arc rectification No tungsten spitting within current range of electrode Compact size requires only a 19 in x 30 in 485 mm x 760 mm footprint SQUARE WAVE TIG 255 OPERATION Strain relief holes in base for welding cables gas and water hoses and control cables Easy access for input connections Connections are simple strip and clamp of input wires no lugs required Low fan noise at idle Return to Section TOC Return to Master TOC Modular construction for easy servicing Simple keypad layout allows even novice users to operate with minimal instruction Unused controls are automatically locked out
122. ster TOC Ojo Fr un 818 EJE pio oO VU cic Return to Section TOC Return to Master TOC F 21 CONTROL BOX PROTECTION SNUBBER BOARD LOCATED ON BACK OF CONTROL BOX TROUBLESHOOTING amp REPAIR PROTECTION SNUBBER BOARD CONTINUITY TEST continued SUPORT CASE BACK AND CENTER BAFFLE WITH WOOD 2 X 4 FIGURE F 5 PROTECTION SNUBBER BOARD LOCATION TEST PROCEDURE 1 2 Remove main supply power to machine Locate and remove all harness plugs from the protection snubber board locat ed on the back of the control box Refer to Figure F 5 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 SQUARE WAVE TIG 255 Inspect board for leaky or burned components If questionable compo nents are observed then replace projec tion snubber board See note Check resistances per Continuity Tablel A f any resistances do not meet the Continuity Table specifications pro jection snubber board is faulty Replace See note Note When installing projection snubber board be sure that the three 8 32 x 1 4 Phillips head mounting screws are tightened securely These conduction points are necessary for high frequency by pass grounding LINCOLN Return to Section TOC Return to Master T
123. t of the Square Wave TIG 255 Refer to Figures B 1 B 2 a and B 2 b and corresponding explanations FIGURE B 1 CONTROL PANEL KEYS Return to Section TOC Return to Master TOC WELD MODE KEYS 5 TIG PULSER KEYS 6 AFTERFLOW KEYS 7 DISPLAY G gt CURRENT CONTROL HF HIGH FREQUENCY JUL TIG PULSER a AFTERFLO Gn 1 CA PULSES PER SECOND Q E ex 6 v Eg 124 Cv LINCOLN 8 SQUARE WAVE 255 gt 2 8 8 EIS 1 2 CURRENT CONTROL KEYS 3 HIGH FREQUENCY KEYS 4 AC WAVE BALANCE KEYS CONTROL PANEL KEYS 4 AC WAVE BALANCE These keys are active in Ojo Fr un 818 EJE pio oO VU cic Return to Section TOC Return to Master TOC The keys are grouped into six areas described below and in Figure B 1 Some areas are active in both TIG and Stick while others are active in TIG only The red LED indicator 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 CURRENT CONTROL These keys select Local or Remote and adjust the Amps Up or Amps Down These key
124. ter TOC Fan runs Display and control Check for proper input Secondary thermostat may be panel dark No output from voltages As per nameplate open Check for glowing yel machine in either Stick or TIG and reconnect panel low light on front panel modes Control transforme may Protection Snubber board may be faulty See Continuity Test Control Board may be faulty Replace Ojo El un 818 EJE gt VU cic CAUTION 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 216 383 2531 or 1 800 833 9353 Return to Section TOC Return to Master TOC LINCOLN E SQUARE WAVE TIG 255 12 95 eme Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo E 2 un 818 EJE plc cic Return to Section TOC Return to Master TOC TROUBLESHOOTING amp REPAIR F 4 TROUBLESHOOTING GUIDE Observe Safety Guidelines detailed in the beginning of this manual PROBLEMS SYMPTOMS POSSIBLE AREAS OF MISADJUSTMENT S OUTPUT PROBLEMS Inspect to assure that the arc start switch is in the on closed position when welding in the TIG Mode RECOMMENDED COURSE OF ACTION Check for loose connectors at the SCR bridge and at the Pr
125. the side louvers Dirt dust or any foreign material that can be drawn into the welder should be kept at a minimum Failure to observe these precautions can result in excessive operating temperatures and nuisance shut downs Square Wave TIG 255 power sources carry an IP23 enclosure rating They are rated for use in damp dirty environments subject to occasional falling water such as rain STACKING Square Wave TIG 255 s cannot be stacked TILTING Each machine must be placed on a secure level surface either directly or on a recommended undercarriage The machine may topple over if this procedure is not followed LINCOLN 5 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 four ways 1 Direct interference radiated from the welder 2 Direct interference radiated from the welding leads 3 Direct interference radiated from feedback into the power lines 4 Interference from re radiation of pickup by un grounded metallic objects Keeping these contributing factors in mind installing equipment per the following instructions should minimize problems 1 Keep the we
126. trol board Close the arc start switch or jumper pins D and E at the six pin amphenol receptacle Check for continuity 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 Test the resistance between 10J6 plug and 10J12 on the projection snubber board Also check resistance from 3J6 plug to 3J12 on the projection snubber board A If zero ohms resistance is indicated test is okay Go If a resistance of any value is shown check wires and connec tions 10J6 MU TS 2 3J6 PLUG J6 REMOVED G2150 SQUARE WAVE 255 CONTROL FIGURE F 8 CONTROL BOARD TEST POINTS SQUARE WAVE TIG 255 TROUBLESHOOTING amp REPAIR ARC START TRIGGER CIRCUIT TEST continued 3J12 3J13 Return to Section TOC Return to Master TOC Qio 9 5 918
127. ttes avec crans lateraux dans les zones ou l on pique le laitier Eloigner les mat riaux inflammables ou les recouvrir afin de pr venir tout risque d incendie d aux tincelles Quand on ne soude pas poser la pince une endroit isol de la masse Un court circuit accidental peut provoquer un chauffement et un risque d incendie S assurer que la masse est connect e le plus pr s possible de la zone de travail qu il est pratique de le faire Si on place la masse sur la charpente de la construction ou d autres endroits loign s de la zone de travail on augmente le risque de voir passer le courant de soudage par les chaines de lev age c bles de grue ou autres circuits Cela peut provoquer des risques d incendie ou d echauffement des chaines et des c bles jusqu ce qu ils se rompent Assurer une ventilation suffisante dans la zone de soudage Ceci est particuli rement important pour le soudage de t les galvanis es plomb es ou cadmi es ou tout autre m tal qui produit des fume s toxiques Ne pas souder en pr sence de vapeurs de chlore provenant d op rations de d graissage nettoyage ou pistolage La chaleur ou les rayons de l arc peuvent r agir avec les vapeurs du solvant pour produire du phosg ne gas forte ment toxique ou autres produits irritants Pour obtenir de plus amples renseignements sur la s ret voir le code Code for safety in welding and cutting CSA Standard W 117 2 1
128. utput stud insulators Diode D1 may be shorted buzzing noise in DC Stick Mode or for cracks or signs of over Check and replace if neces in DC TIG Mode when the arc start heating sary or amptrol is pressed The SCR bridge may be faulty There is no current draw from See Static land Active SCR machine s output studs The machine is not externally loaded Check the polarity switch S2 for correct connections Ojo E El un 818 EJE cic CAUTION 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 216 383 2531 or 1 800 833 9353 LINCOLN 5 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC TROUBLESHOOTING amp REPAIR F 6 Observe Safety Guidelines TROUBLESHOOTING GUIDE detailed in the beginning of this manual PROBLEMS POSSIBLE AREAS OF RECOMMENDED SYMPTOMS MISADJUSTMENT S COURSE OF ACTION OUTPUT PROBLEMS The ammeter displays a very high None 1 The shunt leads 221 and value greater than 316 amps 222 may be loose or open when the machine is not loaded Check the red and white twist Machine may have low or no out ed pair from the shunt to the put control board Refer to wiring diagram Return to Section TOC Return to Master TOC The Control board may be f
129. v g J8 I 24VAC 107 4 NGND I0GND CRYSTAL e sl k L 5V D0 p7 E x xa2 X82 RESET ik M re 335 A D d 475 9 15V 4 6 alus TE lt lt Leno V alon T n D75 85V J6 PIEZO Js wl gt gt lt lt pos N 5V yw 2 L2 di a Lames gt gt OE 1280 J33 gt gt 1 1 3 pt Y 079 078 CONTROL V nono POT OW 10K V HIGH CURRENT BN REM CUR NOLTAGE Dee 0 a 1 EEK 175 RH ae 1 00M 2 2 2 Fi En 0713 1 00K 5 ET en T ps 5 p DISPLAY E a TW 50V x31 ps J3 5 33 nono NGND 7 A 2 100p i00p _ 1000 Jico _ 100p _ roop 1000 100 us N OS 052 US UN 25056 5 Pov Po Titov ov 7 rm 10 CUR FB 44 4 7 2 LCD CONTRAST TEMPERATURE COMPENSATION CIRCUIT 20 041 i C75 LGND 26 7 es 11 V 2 67 LCDGND J3 7 gt 33 2K QE dis T 2 lx J TP3
130. y may be faulty Replace Display A CAUTION 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 216 383 2531 or 1 800 833 9353 SQUARE WAVE TIG 255 Return to Section TOC Return to Master TOC F 9 TROUBLESHOOTING amp REPAIR TROUBLESHOOTING GUIDE Observe Safety Guidelines detailed in the beginning of this manual PROBLEMS POSSIBLE AREAS OF RECOMMENDED SYMPTOMS MISADJUSTMENT S COURSE OF ACTION FUNCTION PROBLEMS AC DC Indicator on control panel None Check leads 304 and 312 for display show AC when polarity proper connections Refer to switch is in the DC position or vice wiring diagram versa machine has output but balance control is not operable in Check microswitch S2A the AC TIG mode located on polarity switch S2 for proper operation Return to Section TOC Return to Master TOC The protection snubber board may be faulty See protection snubber board continuity test Check control transformer T2 See control transformer voltage test If above checks are OK then replace the control board Return to Section TOC Return to Master TOC All red keypad LEDS are dark The wiring harness between but the control panel display is the Control board and the LED operable The machine has output board may be faulty Check
131. ypad lights will turn off The fan will remain on during this period The thermo SQUARE WAVE TIG 255 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 power switch may be left on and the reset should occur within a 15 minute period If the fan is not turn ing or the air intake louvers are obstructed then the input power must be removed and the fan problem or air obstruction be corrected LINCOLN TABLE OF CONTENTS Section F TROUBLESHOOTING amp REPAIR SECTION Q g Troubleshooting amp Repair Section es Section F p Safety ret ue SER esa F 1 5 How to Use Troubleshooting Guide F 1 9 PC Board Troubleshooting Procedures F 2 Troubleshooting F 3 F 15 PC Board Connector Locations 0 4 F 16 Test Procedures Control Transformer Voltage F 17 Protection Snubber Board Continuity F 20 Arc Start Trigger Circuit F 23 cie Wr M F 26 Active SCR MEI F 28 9 Oscilloscope Waveforms Normal Open Circuit Voltage Waveform DC Stick F 31 5 Normal Open Circuit Voltage Waveform AC Stick

Lincoln Electric SVM100-A User's Manual

Contents

Download Pdf Manuals

Related Search

Related Contents