Service Manual
Contents
1. 0 5 Vdc A3 K3 gt Mohm If incorrect replace the defective diodes or the entire diode module 19 With AC DC selector switch 30 in the 0 position make sure voltage on the terminals of the secondary power circuit of transformer 46 approximately 60 Vac with rated mains voltage If incorrect check the connections of the primary and secondary windings of the transformer 46 power circuit considering that each one is made up of two semi windings arranged on the two columns of the magnetic core Perform the tests in par 3 3 1 if necessary Check for voltage at the secondary circuit of the power transformer 46 measuring between terminal A of the thyristor group 47 and terminal C8 of the AC DC selector switch 30 Correct values approximately 61 Vac with power source powered If incorrect perform the tests in par 3 3 1 3 302 221 15 01 07 CEBORA S p A 22 3 3 8 In resistive load operation the output voltage is not regular WARNING FOR THESE TESTS DISCONNECT THE CONNECTOR J4 ON HF BOARD 42 TO PREVENT HIGH FREQUENCY GENERATION OPEN CIRCUIT OUTPUT VOLTAGE TEST Q Output terminals AB and AC of power source voltages according to the table Process Voltage Condition TIG DC 53 Vdc fig 5 2 1a Start button pressed TIG AC 28 Vdc fig 5 2 1b Start button pressed Perform the tests in par 3 3 7 NOTE For the following tests use a resistive load that can2. Power source art 236 76 see file ESP236 76 pdf enclosed at the end of the manual 26 4 2 Components table see file ESP236 76 pdf enclosed at the end of the manual sss 26 43 Spareparts Sta hne HERPES I RARE T ERE PU TER e ELE ha EEEa 26 5 sSELECTRICATL DIAGRAMS gii ipu T HERE U PPAR REC E UTERE PER EErEE aaa 27 5 1 Power source art 236 76 see file SCHE236 76 pdf enclosed at the end of the manual 27 2312 7 WA VELOLMISA ineo a Rep RU DURER rl REB D E RD epe ab di ORT ees 27 5 2 1 Output voltage with open circuit power source par 3 3 7 v eeeesecseescsseeeceseeseeseceeeeeaeeecaeceeeseeneeseens 27 5 2 2 Firing pulses for SCR1 with open circuit power source par 3 3 7 sese 27 5 2 3 Firing pulses for SCR2 with open circuit power source par 3 3 7 sese 27 5 2 4 Output current with power source loaded in table conditions par 3 3 8 sss 28 5 2 5 Output voltage with power source loaded in table conditions par 3 3 8 sss 28 5 2 6 Firing pulses for SCR3 with power source loaded in table conditions par 3 3 8 28 5 3 Mains filter board 51 code 5 600 993 A ccccccssccssscesssecessceesecenseeesseceseeesseeceueeesseeceseseeseeceseeeesaeeneeeenees 29 5 4 Fuse board 4 code 5 602 288 eiae edited treten uceddetedhceustbeadessntd
3. Replace control board 40 3 302 221 15 01 07 CEBORA S p A 24 3 3 9 AC operation arc unstable welding irregular NOTE In AC operation the quality of the welding may be unacceptable due to the oxidation that forms when welding certain materials aluminium and similar To avoid this problem in each period of the welding current specifically each time SCR1 47 engages a high voltage pulse is generated normally 150 250 volts but it may vary depending on the type of material being welded that is applied between torch and workpiece to destroy the oxidation which impedes the passages of current and allow the welding arc to continue For proper operation it is essential to observe the polarity of the power source output and thus the TIG torch must be connected to the terminal AB and the workpiece at the AC terminal of the power source Since the amplitude of the high voltage pulse depends on the type of oxidation that the material presents a special circuit of the control board 40 makes sure that this voltage does not reach levels hazardous for operation of the converter causing SCR2 47 to engage prematurely if necessary The premature engagement of SCR2 47 interrupts a semi period of the welding current which produces poor quality welding Therefore if the welding quality is poor in AC mode make sure it is not due to the partial or total absence of a half period of the welding current This could be due to i
4. a Terminals of solenoid valve 43 approximately 30 Vac in TIG mode with start button pressed the time the solenoid remains open also depends on the post gas set NO Check the wiring between solenoid valve 43 and terminals 1 and 2 of J9 on control board 40 With power source off make sure the resistance between the terminals of solenoid valve 43 approximately 26 ohm If O ohm short circuit replace solenoid valve 43 and control board 40 See CONTROL BOARD 40 POWER SUPPLY TEST par 3 3 1 e START SIGNAL TEST par 3 3 4 Replace control board 40 With power source off make sure the resistance between the terminals of solenoid valve 43 approximately 26 ohm If Mohm winding broken replace solenoid valve 43 Check the presence of the gas at the intake fitting on the rear panel and make sure the pressure and throughput in the input line meet specifications Make sure there are no obstructions in the gas lines of the power source Replace solenoid valve 43 3 302 221 15 01 07 CEBORA S p A 17 3 3 6 In TIG mode gas flows from the torch the arc does not strike no high frequency HF OSCILLATOR TEST a Via the control panel set TIG operation with HF ex Leds L and G lit a HF board 42 discharger SP2 emits discharges at regular intervals with start button pressed YES Check the connections between secondary windings of the power transformer 46 thyristor
5. 45 With the power source off temporarily disconnect the fan 45 terminals from terminal board 52 and check resistance between terminals of fan 45 Correct value 2 50 ohm approximately If incorrect replace the fan 45 Replace the fan 45 Check the wiring between switch 15 terminal board 52 the wired bridges on terminal board 52 and fan 45 terminals Check connections between transformer 46 primary winding and switch 15 3 302 221 15 01 07 CEBORA S p A 13 3 3 3 System powered display and signals do not show the correct values LAMP TEST a On control panel all leds and displays lit for one second after closing the switch 15 Carry out the CONTROL BOARD 40 POWER SUPPLY TEST of par 3 3 1 especially the one referred to J3 Replace the control board 40 PROGRAM INSTALLED TEST a At start up after lamp test display 7 reads the version of the program inserted into control board 40 es PO1 Replace control board 40 ERROR CODE TEST a At start up after lamp test leds J or Y remain lit to indicate an alarm condition TR See Signaling alarm par 3 4 COMMAND AND SIGNALING TEST a With control panel buttons are possible all the Mode and Programs selections as described in the par 3 2 Operative Sequence and in the Instructions Manual Regular operation CURRENT EXTERNAL ADJUSTMENT TEST a Insert a torch with current adjustment
6. Check operation of the AC DC selector switch 30 making sure the closing sequence of the contacts matches the table in the electrical diagram in par 5 1 With the power source off temporarily disconnect the thyristor group 47 and check the integrity of the thyristor group 47 measuring the resistance between terminals A and of the thyristor group 47 Correct values gt Mohm for each measurement point also reversing the test probes If incorrect replace the defective thyristor or the entire thyristor group 47 With AC DC selector switch 30 in 0 position with power source off make sure the diode module 19 is intact measuring the resistance at the following points see drawing par 5 11 Al K2 K1 approximately 0 5 Vdc A1 K2 K1 Mohm A2 Al K2 approximately 0 5 Vdc A2 Al K2 2 2 Mohm A3 4 K3 approximately 0 5 Vdc A3 K3 Mohm If incorrect replace the defective diodes or the entire diode module 19 With AC DC selector switch 30 in 0 position check on terminals of the secondary power circuit of the transformer 46 that voltage approximately 60 Vac with rated mains voltage If incorrect check the connections of the primary and secondary power circuit windings of the transformer 46 considering that each one is made up of two semi windings arranged on the two columns of the magnetic core Perform the tests in par 3 3 1 if necessary
7. and or HF board 42 Check the distance between the tips of the discharger SP2 correct values 0 85 mm HF BOARD 42 COMMAND TEST WARNING FOR THIS TEST DISCONNECT THE CONNECTOR J3 ON HF BOARD 42 TO PREVENT HIGH FREQUENCY GENERATION a HF board 42 connector J4 terminals 1 2 approximately 30 Vac with start button pressed 3 302 221 NO Check the wiring between J4 HF board 42 and J9 control board 40 With power source off temporarily disconnect connector J4 from HF board 42 and check the resistance between terminals 1 2 of J4 on HF board 42 Correct values gt Mohm in both directions If incorrect replace HF board 42 If in short circuit also replace control board 40 15 01 07 CEBORA S p A 18 Check the presence of 30 Vac supply voltage conducting the CONTROL BOARD 40 POWER SUPPLY TEST par 3 3 1 if necessary particularly the one relating to J8 Replace HF 42 and or control 40 boards HF BOARD 42 POWER SUPPLY TEST WARNING FOR THIS TEST RE CONNECT CONNECTOR J3 AND DISCONNECT THE CONNECTOR J4 ON HF BOARD 42 TO KEEP THE HIGH FREQUENCY GENERATION DISABLED a HF board 42 connector J3 terminals 1 2 30 Vac with HF operation set Led L on Check the wiring between J3 HF board 42 and J9 control board 40 With power source off temporarily disconnect connector J3 from HF board 42 and check the resistance between terminals 1 2 of J3 on HF bo
8. there are two low powered thyristors inserted into two similar circuits one of which is always connected and available while the other is parallel connected to the first through a relay when the welding current exceeds approximately 50 Aac Both are controlled by the same driver signal and thus work simultaneously Because of this characteristic in this manual these two thyristors shall be considered as a single one known as SCR3 the shut off thyristor SCR3 and the circuits of the shut off board 48 serve to force SCR2 47 to shut off during AC operation This function simultaneous with the engagement of SCRI 47 makes it possible to generate the high voltage pulse necessary to perforate the oxidation that forms when welding certain materials aluminium and similar and thus makes it possible to maintain the arc when the polarity of the welding current changes This function repeats during each period of the welding current Since the value reached by the high voltage depends on the type of oxidation that the material presents a special circuit of the control board 40 makes sure that this voltage does not reach levels hazardous for operation of the converter If necessary it prematurely engages SCR2 47 In this case welding is poor quality in AC see par 3 3 9 At the converter output on the connection before the output terminal AB of the power source is connected to the HF transformer 28 which appropriately d
9. Operating sequences The following sequences reflect proper machine operation They may be used as guidelines for troubleshooting After each repair they must be carried out without encountering any error or impediment 3 2 1 Control panel commands and signals ti TA TEETIME aan a a C D H M N E A P Q 3 302 221 15 01 07 CEBORA S p A i NOTE a Operations preceded by this symbol refer to operator actions Operations preceded by this symbol refer to machine responses that must occur following an operator action 3 2 2 Power Source TIG operation Connect the gas supply to the fitting on the rear panel Connect the TIG torch to the negative pole AB of the power source Connect the cable of the positive pole AC of the power source to the workpiece Connect the power source to the mains Close the switch 15 on the rear panel in the position corresponding to the mains voltage System powered Oncontrol panel all leds and display light on lamp test After one second display Z shows the version of the program inserted into control board 40 es PO1 Subsequently display Z indicates the programmed current the Mode signaling are lit as set before the last time the unit was shut off V mer gt NO see 3 3 1 3 3 2 3 3 3 YES a Press the button E several times the Mode selection is repeated in sequence a Press the button P several ti
10. group 47 inductor 50 AC DC selector switch 30 HF transformer 28 e output terminals AB e AC of the power source If you find loose connections tighten them and replace any components with damaged terminals Check operation of the AC DC selector switch 30 making sure the closing sequence of the contacts matches the table in the electrical diagram in par 5 1 Make sure that there is no short circuit between terminals J1 and J2 of HF board 42 or in the connection of the primary circuit of HF transformer 28 Check the integrity of the HF filter board 41 particularly the status of the 3 capacitors the earth connection of the board and the connections between terminals TP1 of HF filter board 41 with AC output terminal of the power source and TP2 of HF filter board 41 with the shared point between inductor 50 and HF transformer 28 If you find damaged components or connections replace HF filter board 41 Make sure that the output terminals AC and AB of the power source gifas are not in isolation leak thus that there are no high voltage surface discharges Replace with new ones if necessary Check the torch and torch cable if worn or damaged replace Go to par 3 3 7 open circuit operation Make sure the connection between terminals J1 and J2 of HF board 42 with the primary circuit of the HF transformer 28 is not broken If necessary restore the connection or replace HF transformer 28
11. or those on J2 of control board 40 Check presence of 7 Vac supply voltage if necessary performing the CONTROL BOARD 40 POWER SUPPLY TEST par 3 3 1 especially those related to J6 Replace control 40 and or shut off 48 boards Check connections between secondary windings of the power transformer 46 thyristor group 47 inductor 50 AC DC selector switch 30 HF transformer 28 and output terminals AB and AC of the power source If you find loose connections tighten them and replace any components with damaged terminals Check operation of the AC DC selector switch 30 making sure the closing sequence of the contacts matches the table in the electrical diagram in par 5 1 With the power source off temporarily disconnect the thyristor group 47 and make sure the thyristor group 47 is intact by measuring the resistance between terminals A and of the thyristor group 47 Correct values gt Mohm for each measurement point also reversing the test probes If incorrect replace the defective thyristor or the entire thyristor group 47 With AC DC selector switch 30 in the 0 position with the power source off make sure the diode module is intact by measuring the resistance on the following points see drawing par 5 11 3 302 221 15 01 07 CEBORA S p A 21 AI K2 4 K1 20 55 Vdc AI K2 Kl 4 gt Mohm A2 Al K2 20 5 Vdc A2 Al K2 gt Mohm A3 K3
12. potentiometer cursor 6 5 Vac input to pulse generator for SCR1 power supply on control board 40 dual 6 5 Vac input to pulse generators for SCR2 and SCR3 power supply on control board 40 oxide destruction high voltage pulse signal input NU gate command output for SCR2 47 NU gate command output for SCR3 SC1 and SC2 on shut off board 48 gate command output for SCR1 47 input 26 Vac to protection circuit power supply input signals from thermostats and cooling unit AC operation enable input solenoid valve 43 command output 2nd shut off circuit enable relay command input on shut off board 48 AC power supply output to HF board 42 power circuit power supply 27 Vac command output for HF enable relay converter output voltage signal input earth connection 15 01 07 CEBORA S p A 31 5 6 Shut off board 48 code 5 602 289 5 6 4 Topographical drawing O qui L E d FISS1 FEES EL d 5 6 2 Connector table Conn Terminals Function JI 1 K 3 G gate command input for SCR1 47 JI 2 K 4 G gate command output for SCR1 47 J2 1 2 2nd shut off circuit enable relay command input on shut off board 48 J3 1 G 2 K gate command input for SCR3 SC1 and SC2 on shut off board 48 J3 5 G 2 K gate command input for SCR2 47 J3 6 G 4 K gate command output for SCR2 47 J4 oxide destruction high voltage pulse signal output referring to J3 2 o
13. symbol refer to actions that the operator must carry out to solve problems solutions 3 3 1 The power source does not start control panel off MAINS SUITABILITY TEST a No voltage for mains protection poco Eliminate any short circuits or insulation losses on the connections between power cable switch 15 terminal board 52 transformer 46 primary winding services transformer 4 fan 45 and socket 12 on rear panel Make sure wiring between mains cable switch 15 and transformer 46 primary winding with particular care to the connections that perform mains voltage adjustment and between transformer 46 secondary winding and terminals A of scr group 47 and C8 of switch AC DC 30 If you find damage connections restore them or devices in short circuit replace them Mains not suitable to power the power source ex insufficient installed power MAINS CONNECTION TEST Q Switch 15 terminals U and W 230 Vac with both mains at 208 Vac or 230 Vac Check power cable and plug and replace if necessary Make sure wiring between mains cable switch 15 and transformer 46 primary winding with particular care to the connections that perform mains voltage adjustment and between transformer 46 secondary winding and terminals A of scr group 47 and C8 of switch AC DC 30 If you find damage connections restore them or devices in short circuit replace them Check operation of
14. the service transformer 4 and the secondary synchronization circuit leading to connector J4 The control board 40 is the heart of the power source It supervises management of the other boards with more specialized functions regulates the welding current by generating the pulses to send to the thyristors 47 It contains the microprocessor that manages all of the functions of the power source including those that interface with the user obtained via the control panel built into the board itself The signal of the power source output voltage is drawn from the output terminals of the converter Appropriately filtered by the snubber board 6 this signal continues toward the control board 42 where it is used to check for any presence of hazardous voltage at the power source output see par 3 4 1 ee 99 3 302 221 15 01 07 CEBORA S p A The snubber board 6 also includes the load resistors for SCR1 and SCR2 47 which make it possible for SCR1 and SCR2 47 to function correctly even with an open circuit power source and the capacitor C1 which helps strike the arc in DC mode The connector 13 on the rear panel of the power source is connected to the pressure switch on the cooling unit it is connected in series to the thermostats on transformer 46 and inductor 50 on the same alarm line that reaches the control board 40 When the cooling unit is not connected it is necessary to make a bridge on connector 13 betwe
15. two secondary service circuits all windings are made up of two half windings arranged on the two columns of the magnetic core One 30 Vac service winding powers the circuits for the signals that dialogue outside the power source through the connector board 49 The second service winding a 27 Vac powers the thermal protection circuits of the power source thermostats on inductor 50 and transformer 46 and to measure the pressure of the liquid in the cooling unit The secondary power circuit of the transformer 46 is connected to the current converter made up of the thyristor group 47 SCRI and SCR2 the diode module 19 D1 D2 D3 the inductor 50 and the AC DC selector switch 30 The electrical diagram of the power source in par 5 1 shows the operating table of the AC DC selector switch 30 Based on the position of the AC DC selector switch 30 the converter acts as a Half controlled rectifier to generate and regulate direct current or as static switch to generate and regulate alternating current in the latter instance the frequency of the alternating output current corresponds to the supply voltage frequency of the power source The SCR1 and SCR2 47 receive the driver signals from the control board 40 through the shut off board 48 and the output current is regulated by the control board 40 by changing the firing angle of SCR1 and SCR2 47 3 302 221 15 01 07 CEBORA S p A i NOTE In the shut off board 48
16. 0 Conn J2 terminals 1 2 approximately 900 ohm Conn J3 terminals 4 1 4 2 gt Mohm Conn J3 terminals 4 5 4 6 gt Mohm Conn J5 terminals 1 2 gt Mohm Conn J6 terminals 5 4 5 6 gt Mohm Conn J6 terminals 1 2 gt Mohm Conn J8 terminals 1 2 gt Mohm If incorrect replace control board 40 With power source off temporarily disconnect connectors J2 J3 J5 J6 and J8 on control board 40 Power up again and check once more for the presence of voltage on the connectors of control board 40 Conn J2 terminals 1 2 16 Vac fuse F4 on fuse board 4 Conn J3 terminals 4 1 24 2 16 Vac fuse F1 on fuse board 4 Conn J3 terminals 4 5 24 6 8 Vac fuse Fl on fuse board 4 Conn J5 terminals 1 2 22 Vac Conn J6 terminals5 4 25 6 7 Vac fuse F3 on fuse board 4 Conn J6 terminals 1 2 7 Vac fuse F2 on fuse board 4 Conn J8 terminals 1 2 30 Vac If incorrect make sure the fuses F1 F2 F3 on fuse board 4 are intact or replace fuse board 4 or service transformer 4 or power transformer 46 Replace control board 40 3 302 221 15 01 07 CEBORA S p A 12 3 3 2 Power source powered control panel on fan 45 stopped FAN 45 TEST O Fan 45 terminals on terminal board 52 230 Vac with switch 15 closed and mains voltage both at 208 or 230 Vac o lt gt YES Make sure that there are no mechanical impediments blocking the fan
17. 30 in the 0 position power the power source with J4 on control board 40 disconnected and check the voltage on J4 of control board 40 terminals 3 and 2 15 Vdc terminals 1 and 2 15 Vdc If incorrect replace control board 40 Replace current transducer 5 and or control board 40 CURRENT OUTPUT TEST WITH OPEN CIRCUIT POWER SOURCE Q Control board 40 connector J4 terminals 4 2 0 Vdc 20 mVdc with start button pressed output current signal with open circuit power source Check the wiring between current transducer 5 and J4 control board 40 With power source off temporarily disconnect J4 from control board 40 and check the resistance on terminals 4 and 2 of J4 on control board 40 approximately 9 Kohm If incorrect replace control board 40 Make sure there are no leaking or short circuited components connected to the power source output terminals Replace current transducer 5 Replace control board 40 3 302 221 15 01 07 CEBORA S p A 20 FIRING PULSES FOR SCRI 47 AND SCR2 47 TEST NOTE In AC operation the output voltage becomes alternating only in presence of output current thus SCR2 is not driven in AC operation with open circuit power source a Shut off board 48 connector J1 terminals 2 and 4 gnd fig 5 2 2a pulses for SCRI with AC DC selector switch 30 in the 0 position With AC DC selector switch 30 in pos AC or DC the w
18. ALVE 44 3065118 FAN 45 3165051 MOTOR 46 5610096 TRANSFORMER 47 5605539 SCR GROUP 48 5602289 CIRCUIT 49 5602292 CONNECTOR CIRCUIT 50 3205314 INDUCTOR LEE Sl ALL CONSUMABLES AND REPAIR PARTS SHOULD BE ORDERED THROUGH YOUR SNAP ON DEALER ZHO9 AOEC 80C JU Ivy QOS63Li Cdl Edl V v ka a aa LOOHHVY
19. CEBORA S p A TIG 250 AC DC POWER SOURCE art 236 76 SERVICE MANUAL 15 01 07 3 302 221 CEBORA S p A CONTENTS 1 GENERAL INFORMATION 2 e dese pisce erede save ah seas doce tdg is eo ere dade ass esee Ba kaea as oei Seas 3 LAY Introd ction 5 oon ete pieta qu ei SEE e HERE das SE VI RE De ed eque CEEA tet Ras doca Pap A do tege 3 1 2 General service poliey id tede a dan dando sie eai o piedi e tee eser PIRERE ea den dre VIR Ee e ede ees 3 I3 Safety informal on cia Sco aere bete ro eee tetas E PO e eR Oque seo cesar rb ee aea ba GAS ot E E 3 14 Electromagnetic compatibility ore Ee rre a eee nine Gare ee ok ee De PES bu ah epe Pubs 3 2 SYSTEM DESCRIPTION 5 ete o ette E PORE En ne be EO RED EEEE epe erue iE SEE aceite 4 ZL Intr ducti n iter RE RR ERE Ege ER ARE DESEE EUER RE ES Dai Pre Sh e D PESE Ge eee og 4 2 2 xTechnicalspecifications e etre tere E RE EH EXE E EA ceara busca Te rapa TE HER ERR TNR 4 2 3 Description of TIG 250 AC DC power source esesseeeeeeeeeeneeennennen nennen nennen trennen ene te nnne nennen 4 3 MAINTENANCE inr bestie ep rie HE e PIPER COSTA LESS LIDE C um de tou ea RU EUR deter 7 3i Periodic inspection clearings 2 IUE EU Re eite PER ci teo qa sb ras dna essa sides 7 32 Oper tmg Sequences i sere er em UR PERI ER RR t Rn quiuis deter ole E HERE alada 7 3 2 1 Control panel commands and signals sees eere nennen nenne
20. S TEST a Shut off board 48 connector J3 terminals 1 and 2 gnd fig 5 2 6 pulses for SCR3 in the AC operation and power source loaded in table conditions Check the wiring between J3 shut off board 48 and J7 control board 40 Replace shut off 48 and control 40 boards POWER SOURCE LOADED OUTPUT CURRENT TEST a Control board 40 connector J4 terminals 4 2 3 2 Vdc fig 5 2 4a in DC and 3 2 Vac fig 5 2 4b in AC with start button pressed and power source loaded in table conditions Replace control board 40 Check the wiring between current transducer 5 and J4 control board 40 Make sure the current transducer 5 is properly mounted on the connector cables between AC DC selector switch 30 and AC of the power source output terminal With the power source off temporarily disconnect J4 from control board 40 and check the resistance on terminals 4 and 2 of J4 on control board 40 approximately 9 Kohm If incorrect replace control board 40 Check the integrity of the power transformer 46 and inductor 50 If they show any signs of damage or burns replace Check connections between secondary windings of the power transformer 46 thyristor group 47 inductor 50 AC DC selector switch 30 HF transformer 28 and output terminals AB and AC of the power source If you find loose connections tighten them and replace any components with damaged terminals
21. SCR2 with open circuit power source par 3 3 7 3 302 221 15 01 07 CEBORA S p A 28 4 00ms A Lineas 0 00 V 2 00 V 2 00 V padoms A Linea 0 00 V 0560 00 050 00 5 2 4a 5 2 4b 5 24 Output current with power source loaded in table conditions par 3 3 8 TekArrsta F J Pk Arresta rm 4 il 100V C7777777775 00ms A Lineas 0 00 V 10 0V C7777777779 00ms A linea 0 00 V 150 00 50 00 5 2 5a 5 2 5b 5 25 Output voltage with power source loaded in table conditions par 3 3 8 Tek Arrest E m 2 00 V P 10 0us Al Chi 7 0 00 V 15 50 00 5 2 6 Firing pulses for SCR3 with power source loaded in table conditions par 3 3 8 3 302 221 15 01 07 CEBORA S p A 29 5 3 Mains filter board 51 code 5 600 993 A 5 3 1 Topographical drawing 5 3 2 Connector table Conn Terminals Function TP1 earth connection TP2 mains input phase R TP3 mains input phase S 5 4 Fuse board 4 code 5 602 288 5 4 1 Topographical drawing 5 4 2 Connector table Conn Terminals Function J1 1 4 0v 2 dual 16 Vac output to control board 40 power supply 15 Vdc J1 5 4 0v 6 dual 8 Vac output to control board 40 power supply 5 Vdc J2 1 2 6 5 Vac output to pulse generators for SCR1 power supply on control board 40 J2 4 5 0v 6 dual 6 5 Vac output to pulse generators for SCR2 and SCR3 power supply on contro
22. aesneas 29 5 5 Control board 40 code 5 602 293 A er raererer er tente enen trennen enne ne ene tese nr ennt nene 30 5 6 Shut off board 48 code 5 602 289 eene nennen nennen etre trennt nre tne ne ene tenn nein nenne 31 5 7 Snubber board 6 code 5 602 294 sssssssssssssessseseseeeee eene enne entes ren tentent rns en nennen nennen nnne 32 5 8 HF board 42 code 5 602 290 eise ee tiere ete arien E re artnet ere iaae A Eei EE ea ar 32 5 9 HF filter board 41 code 5 602 291 sss eene enne nennen nenne nre nne ne ene tenn trennen ene 33 5 10 Connector board 49 code 5 602 292 n si eane a ee Ee a eene enne entree enter innere DOVE eren nennen nnns 33 5 11 Diode group 19 code 3 200 090 4 rr ch as ease nennen eene ne raca trennen entente teen 34 3 302 221 15 01 07 CEBORA S p A i 1 GENERAL INFORMATION 1 1 Introduction The purpose of this manual is to train personnel assigned to carry out maintenance on the TIG 250 AC DC Power Source art 236 76 1 2 General service policy It is the responsibility of the customer and or operator to use the equipment appropriately in accordance with the instructions in the Instructions Manual as well as to maintain the equipment and related accessories in good working condition in compliance with the instructions provided in the Service Manual Any internal inspection or repairs must be carried out by qua
23. ard 42 Correct values gt Mohm in both directions If incorrect replace HF board 42 If in short circuit also replace control board 40 Check for the presence of 30 Vac supply voltage performing if necessary the CONTROL BOARD 40 POWER SUPPLY TEST par 3 3 1 especially the one relating to J8 Go to par 3 3 7 Replace HF board 42 3 302 221 15 01 07 CEBORA S p A 19 3 3 7 In open circuit operation the output voltage is not regular WARNING FOR THESE TESTS DISCONNECT THE CONNECTOR J4 ON HF BOARD 42 TO PREVENT HIGH FREQUENCY GENERATION OPEN CIRCUIT VOLTAGE OUTPUT TEST a Output terminal AB and output terminal AC of the power source voltages according to the table Process Voltage Condition TIG DC 53 Vdc fig 5 2 1a Start button pressed TIG AC 28 Vdc fig 5 2 1b Start button pressed Regular operation CURRENT TRANSDUCER 5 POWER SUPPLY TEST Q Control board 40 terminals 3 and 2 15 Vdc terminals 1 and 2 15 Vdc approximately Check the wiring between current transducer 5 and J4 control board 40 With power source off temporarily disconnect the connector J4 from control board 40 and check the resistance between terminals 3 and 2 and terminals 1 and 2 of the patch connector disconnected from J4 Correct values approximately 30 40 Kohm If incorrect replace current transducer 5 With AC DC selector switch
24. aveform becomes fig 5 2 2b a Shut off board 48 connector J3 terminals 4 and 6 gnd fig 5 2 3a pulses for SCR2 with AC DC selector switch 30 in the 0 position With AC DC selector switch 30 in pos DC the waveform becomes fig 5 2 3b SCR2 is not driven with selector switch in position AC NO Check the wiring between J1 shut off board 48 and SCR1 47 and between J3 shut off board 48 and SCR2 47 Check the wiring between J1 J3 of shut off board 48 and J7 of control board 40 With power source off temporarily disconnect terminals 2 and 4 of J1 on shut off board 48 and check the resistance between patch terminals removed from J1 gate cathode junction of SCRI Correct values approximately 20 ohm If incorrect replace SCRI 47 or the complete thyristor group With power source off temporarily disconnect terminals 4 and 6 of J3 on shut off board 48 and check the resistance between patch terminals removed from J3 gate cathode junction of SCR2 Correct values approximately 20 ohm If incorrect replace SCR2 47 or the complete thyristor group Check for the presence and phase of the 16 Vac synchronization signal on J2 of control board 40 This signal must have the proper phase ratio with the secondary voltage of the power transformer 46 If incorrect reverse the wires of the primary circuit of the service transformer 4 on terminal board 52 or those on J3 or J4 of fuse board 4
25. duces no effect START SIGNAL TEST a Control board 40 connector J5 terminals 3 and 4 approximately O Vac with start button pressed 26 Vac with button released NO Check the wiring between J5 control board 40 and TP2 and TP3 on connector board 49 Make sure the torch connector is properly connected on CN1 connector board 49 and that the START button on the torch is working properly With power source off temporarily disconnect the connector J5 from control board 40 and check the resistance between terminals 3 and 4 of J5 control board 40 Correct values junction of a diode in both directions for this measurement the voltage at the diode junction can be between 0 5 and 1 Vdc approximately If incorrect replace control board 40 Check the power supply to the control board 40 performing the CONTROL BOARD 40 POWER SUPPLY TEST in par 3 3 1 if necessary Make sure the tracks of the printed circuit on connector board 49 match checking the continuity of the following connections Conn CNI terminal 1 TP2 Conn CNI terminal 2 TP3 Conn CNJ terminal 3 TP4 Conn CNJ terminal 4 TP5 Conn CNI terminal 5 TP6 If you find broken tracks restore them or replace connector board 49 Replace connector 49 and or control 40 boards Replace control board 40 3 302 221 15 01 07 CEBORA S p A 16 3 3 5 In TIG mode no gas flows from the torch SOLENOID VALVE 43 TEST
26. en terminals 1 and 3 to prevent the power source from remaining blocked The fan 45 to cool the power elements of the power source is powered directly by terminal board 52 and therefore always at 230 Vac On the front panel is the connector board 49 which acts as an interface for the power source input and output signals It dialogues directly with the control board 40 and contains the filters to eliminate disturbances on the power source input and output signals These signals include Power source start from torch trigger External adjustment of the welding current via external potentiometer The signals processed by the electronic boards and present at their connectors are listed in the tables in chapter five of this manual 3 302 221 15 01 07 CEBORA S p A 3 MAINTENANCE WARNINGS ANY INTERNAL INSPECTION OR REPAIRS MUST BE CARRIED OUT BY QUALIFIED PERSONNEL UNPLUG THE POWER SOURCE FROM THE MAINS BEFORE REMOVING THE PROTECTIVE COVERS AND ACCESSING THE INTERNAL PARTS 3 1 Periodic inspection cleaning Periodically remove any dirt or dust to ensure smooth air flow and thus keep the internal elements of the power source cool Check the conditions of the output terminals the output and power cables of the power source replace if damaged Check the conditions of the internal power connections on the electronic boards if you find loose connections tighten them or replace the connectors 32
27. ency is then generated to start the arc as well as the power source output DC voltage AC voltage is generated only if output current in present After approximately three seconds the output voltage and high frequency are no longer generated TIG operation stops if there is no current at the power source output after start and the post gas stage begins NO see 3 3 6 3 3 7 i YES Q Use the knob AA to set the current based on the welding you intend to perform a Move the torch near the workpiece and press the torch trigger Begin welding Turn the knob AA or the torch potentiometer to obtain the current level suitable for the type of welding to be done During welding display Z indicates the welding current NO see 3 3 3 3 3 8 i YES a Release the torch start button The arc shuts off immediately if long ramp times are not set Gas continues to flow for the entire post gas time NO see 3 3 5 i YES REGULAR OPERATION 3 302 221 15 01 07 CEBORA S p A 10 3 3 Troubleshooting WARNINGS ANY INTERNAL INSPECTION OR REPAIRS MUST BE CARRIED OUT BY QUALIFIED PERSONNEL UNPLUG THE POWER SOURCE FROM THE MAINS BEFORE REMOVING THE PROTECTIVE COVERS AND ACCESSING THE INTERNAL PARTS NOTE The problems the machine may suffer symptoms are indicated in boldface a Operations preceded by this symbol refer to situations that the operator must check into causes Operations preceded by this
28. h this alarm the power source does not deliver current but the fan 45 continues operating for rapid cooling Normal operation is automatically restored when the temperature returns within the allowed limits If the alarm is due to the pressure of the coolant fluid check operation of the cooling unit see Cooling Unit Service Manual To identify the origin of the blockage it is possible to cut out the cooling unit by connecting together terminals 1 and 3 of the connector 13 on the rear panel of the power source or insert the special connector provided with the power source In case of overtemperature Make sure the fan 45 is working properly see par 3 3 2 Check for proper air flow and make sure there is no dust or blockage to cooling of the internal components Make sure that operating conditions meet specifications in particular observe the duty cycle Check the wiring connections between terminals 3 and 4 of J8 on control board 40 thermostat in the transformer 46 thermostat in the inductor 50 and connector 13 on the rear panel of the power source Make sure voltage O Vac short circuit on J8 of control board 40 terminals 3 and 4 If incorrect with the power source off temporarily disconnect the thermostats and the connector 13 and check the resistance of each at ambient temperature the thermostat contacts must be closed and with the appropriate fluid pressure the pressure switch contact mu
29. l board 40 J3 1 2 230 Vac mains input to power service transformer 4 J4 1 2 16 Vac output synchronization signal for control board 40 Fuse Value Function F1 2 A 230 Vac power supply for service transformer 4 F2 0 5 A 6 5 Vac power supply for pulse generator SCRI on control board 40 F3 2A dual 6 5 Vac power supply for pulse generators for SCR2 and SCR3 on control board 40 F4 0 5 A 16 Vac output synchronization signal for control board 40 3 302 221 15 01 07 CEBORA S p A 30 5 5 Control board 40 code 5 602 293 A 5 5 1 5 5 2 3 302 221 Topographical drawing Connector table Terminals 1 2 1 2 1 4 0v 2 5 4 Ov 6 1 2 3 4 1 2 3 4 5 6 80 7 1 2 4 5 0v 6 1 3 gnd 2 4 G 3 K 5 6 G 3 K 8 G 7 K 1 2 Function NU 16 Vac input synchronization signal for control board 40 dual 16 Vac input to control board 40 power supply 47 15 Vdc dual 8 Vac input to control board 40 power supply 4 5 Vdc 15 Vdc output to current transducer 5 power supply O Vdc output to current transducer 5 power supply 15 Vdc output to current transducer 5 power supply power source output current signal input 26 Vac input to start command circuit power supply on control board 40 start signal input NU 5 Vdc output to external current potentiometer power supply reference current signal input from external
30. l built into the power source 2 2 Technical specifications To check the technical specifications see the plates affixed to the equipment the Instruction Manual and the Sales Catalogue 2 3 Description of TIG 250 AC DC power source The TIG 250 AC DC is a controlled current power source made up of a single phase transformer and a converter that can be configured as a rectifier bridge for direct current applications or as a static switch for alternating current applications The configuration may be selected using the AC DC selector switch 30 AF on the front panel Referring to the electrical diagram in par 5 1 drawing 4 1 and table 4 2 one may identify the main blocks that make up the power source The main switch 15 on the rear panel directly powers the transformer 46 and the terminal board 52 to which are connected the various internal services of the power source The power source can operate with either mains at 208 Vac or at 230 Vac depending on the setting of switch 15 As an effect of the primary circuit of the transformer 46 which acts as an autotransformer the terminal board 52 and thus all internal services connected to it are always powered at 230 Vac The mains filter board 51 connected to the terminal board 52 contains the filter to reduce conducted interference reflected in the mains The transformer 46 has a second power winding with voltage and current values suitable for welding and
31. lified personnel who are responsible for any intervention on the equipment It is forbidden to attempt to repair damaged electronic boards or modules replace them with original Cebora spare parts 1 3 Safety information The safety notes provided in this manual are an integral part of those given in the Instruction Manual Therefore before working on the machine please read the paragraph on safety instructions in the aforementioned manual Always disconnect the power cord from the mains before accessing the interior of the equipment Some internal parts such as terminals and dissipaters may be connected to mains or otherwise hazardous potentials It is therefore forbidden to work with the safety guards removed from the machine unless strictly necessary In this case take special precautions such as wearing insulating gloves and footwear and working in a perfectly dry environment with dry clothing 1 4 Electromagnetic compatibility Please read and observe the instructions provided in the paragraph Electromagnetic compatibility of the Instruction Manual 3 302 221 15 01 07 CEBORA S p A 2 SYSTEM DESCRIPTION 2 1 Introduction The TIG 250 AC DC is un electronic power source suitable for AC DC TIG welding with high frequency arc striking It may be used together with a range of accessories for various types of applications see list in the Sales catalogue The operator interface is developed via the control pane
32. mes the Cicle selection is repeated in sequence Each time the button E is pressed the leds G H M and N light in sequence together with one of leds F or L that lit alternatively one each other Each time the start button P is pressed the leds Q S T R V U W and X light in sequence according with the Mode selected Memes gt NO see 3 3 3 YES Oooo odo WARNINGS DURING THE FOLLOWING TESTS DO NOT AIM THE TORCH AT PEOPLE OR PARTS OF THE BODY BUT ONLY TOWARDS AN OPEN SPACE OR THE WORKPIECE DO NOT TRY TO MEASURE THE OUTPUT VOLTAGE DURING THESE STEPS THE PRESENCE OF HIGH FREQUENCY MAY DAMAGE THE INSTRUMENT OR THE POWER SOURCE ITSELF a With switch AC DC 30 select the TIG DC or TIG AC process O Use the button E to select the TIG CONTINUOUS with HF 2 STAGE Mode leds L and G lit a Briefly press the torch start button With switch AC DC 30 in DC position led C remains lit and led D off With switch AC DC 30 in AC position led D remains lit and led C off 3 302 221 15 01 07 CEBORA S p A Gas begins flowing from the torch for as long as the button is held down Gas continues to flow from the torch for the duration of the post gas time set led X lit even after the start button is released NO see 3 3 3 3 3 4 3 3 5 i YES a Press the start button and hold it down for approximately 5 seconds Gas output begins the high frequ
33. mproper operation of the shut off circuit and it is therefore recommended that you check correct operation of the shut off circuit of SCR2 47 performing if necessary the SCR3 ENABLE TEST FOR AC OPERATION and START PULSES TEST FOR SCR3 in par 3 3 8 that the high voltage pulse to destroy oxidation measurable on control board 40 connector J7 terminals 1 and 3 is always below the premature engagement threshold of SCR2 47 set at approximately 500 Vdc 3 302 221 15 01 07 CEBORA S p A 25 3 4 Alarm signals 3 4 1 Led Y off Power source output voltage greater than 48 Vac Alarm active only in AC operation For safety reasons the power source is blocked if the voltage at its output exceeds 48 Vac in AC operation In open circuit AC operation the power source has an output voltage of approximately 28 Vdc since only SCRI is controlled while SCR2 is controlled only when the welding current is already present at the power source output Control of hazardous AC voltage at the power source output is activated to make sure that any breakdown in the control circuits or short circuited thyristor generates alternating voltage with the open circuit power source To analyze the problem see open circuit operation par 3 3 7 loaded operation par 3 3 8 and AC operation par 3 3 9 3 4 2 Led F on Temperature of the transformer 46 or inductor 50 too high or low pressure of the coolant fluid Wit
34. n enne enne neen rennen ene 7 3 2 2 Power Source TIG Operation ie oe iG ass GAS Loss HO eo Re Urn RH er rte boss oai mec iret 8 3 3 Troubleshooting eee eee ie pite Rr and ee do E re d eom de HE Pp eite 10 3 3 1 The power source does not start control panel off sese 10 3 3 2 Power source powered control panel on fan 45 stopped sse 12 3 3 3 System powered display and signals do not show the correct values seeeeeeeee 13 3 3 4 The start button produces no effect eene nennen nenne nennen ennt ene te nnne 15 3 3 5 In TIG mode no gas flows from the torch essen eene nennen nenne enne enne 16 3 3 6 In TIG mode gas flows from the torch the arc does not strike no high frequency 17 3 3 7 In open circuit operation the output voltage is not regular eee 19 3 3 8 In resistive load operation the output voltage is not regular eene 22 3 3 9 AC operation arc unstable welding irregular eee 24 34 Alam SINAIS es seii eee rt o EHE RH ei E de ERI e ED detis 25 3 4 1 Led Y off Power source output voltage greater than 48 Vac sess 25 3 4 2 Led F on Temperature of the transformer 46 or inductor 50 too high or low pressure of the coolant Tlind iiaisiie ende ODE RE RU 25 4 COMPONENTS LIST irre ri PER ED HERR REUS ERE Up HER CE ears 26 4
35. n shut off board 48 3 302 221 15 01 07 CEBORA S p A 32 5 7 Snubber board 6 code 5 602 294 5 7 1 Topographical drawing 5 7 2 Connector table Conn Terminals Function J1 1 converter output voltage input potential J1 2 converter output voltage input potential J2 1 2 converter output voltage signal output 5 8 HF board 42 code 5 602 290 5 8 1 Topographical drawing 5 8 2 Connector table Conn Terminals Function J1 J2 output for HF transformer 28 J3 1 2 AC power supply input to HF board 42 power circuit power supply J4 1 2 27 Vac command input for HF enable relay 3 302 221 15 01 07 CEBORA S p A 33 5 9 HF filter board 41 code 5 602 291 5 9 1 Topographical drawing 5 9 2 Conn 5 10 Connector table Terminals Function TP1 TP2 converter output voltage input TP7 earth connection Connector board 49 code 5 602 292 5 10 1 Topographical drawing 5 10 2 Connector table Conn CNI CNI CN1 CNI CNI CNI CN2 3 302 221 Terminals 1 2 3 5 4 6 7 8 9 10 11 12 13 14 TP1 TP7 TP2 TP3 TP4 4 TP6 TP5 Function start signal input 5 Vdc output to external current potentiometer power supply reference current signal input from external potentiometer cursor NU earth connection NU earth connection start signal output 5 Vdc input to external current p
36. otentiometer power supply reference current signal output from external potentiometer cursor earth connection 15 01 07 CEBORA S p A 5 11 Diode group 19 code 3 200 090 A 5 11 1 Assembly drawing A1 K2 A3 K1 A2 D1 D2 amp Ki A 3 302 221 D3 K3 34 15 01 07 Part Ref Model Description TIG250 1 5801298 LEFT SIDE PANEL 2 5803803 SUPPORT 3 5803775 COVER 4 5610097 AUXILIARY TRANFORMER 5 5710307 TRANSDUCER 6 5602294 SNUBBER CIRCUIT 7 5802855 CENTER DEVIDER 8 5803876 GAS CYLINDER SUPPORT 9 CKS251028 BELT 10 3175603 FUSE HOLDER 11 3175563 FUSE 12 3175370 SOCKET 13 3170235 CONNECTOR 14 3060431 SUPPORT 15 3190132 SWITCH 16 CKS250874 STRAIN RELIEF 17 CKS251110 INPUT CABLE 18 5802477 BACK PANEL 19 3200090 RECTIFIER 20 5801297 RIGHT SIDE PANEL 21 CKS251094 CAP 22 CKS251098 FIXED WHEEL 23 3080052 AXLE 24 5803804 SUPPORT 25 5803805 SUPPORT 26 5801773 BOTTOM 27 5800527 SUPPORT 28 5610055 HF TRANSFORMER 29 3130079 WHEEL 30 3190517 SWITCH 31 5802183 FRONT PANEL 32 3175354 CONNECTOR 33 5802184 FRONT PANEL 34 3070015 PROTECTION 35 3070336 FRAME 36 5803956 HANDLE 37 3060247 SUPPORT 38 CKS250920 KNOB 39 CKS251089 KNOB 40 5602293 MICRO CIRCUIT 41 5602291 FILTER CIRCUIT 42 5602290 HF CIRCUIT 43 CKSB7105370 SOLENOID V
37. potentiometer When the potentiometer on the torch is adjusted the value shown on the display Z will change Make sure the torch connector is correctly inserted on connector AE on Power Source front panel 3 302 221 15 01 07 CEBORA S p A 14 With the power source off temporarily disconnect torch signal connector from connector AE of the Power Source and check on connector AE terminals 3 4 and 4 voltage 5 Vdc current external adjustment potentiometer power supply If incorrect temporarily disconnect with the power source off connector J5 from control board 40 and make sure restarting the Power Source on terminals 6 and 8 of J5 on control board 40 voltage 5 Vdc If not correct replace control board 40 Make sure with torch inserted on connector AE of Power Source voltage on terminals 7 and 8 of J5 on control board 40 Corrected value from 0 to 5 Vdc by turning torch potentiometer If not correct check wiring between J5 control board 40 connector board 49 and torch potentiometer and if necessary replace connector board 49 If correct replace control board 40 Replace the connector 49 and or control 40 boards Check the supply voltages of control board 40 performing the CONTROL BOARD 40 POWER SUPPLY TEST in par 3 3 1 especially the one referred to J3 Replace control board 40 3 302 221 15 01 07 CEBORA S p A 15 3 3 4 The start button pro
38. riven by the HF board 42 generates high voltage and high frequency to strike the arc in TIG welding Operation of the HF board 42 is dependent upon the presence of 27 Vac alternating voltage on the connector J9 terminals 5 and 6 of control board 40 HF board 42 power stage power supply and the HF start command on the connector J9 terminals 7 and 8 of control board 40 HF relay start command The connection before the A AC output terminal of the power source hosts the Hall effect current transducer 5 which sends to the control board 40 the output current feedback signal used to regulate the welding current Near the output terminals of the power source is the HF filter board 41 which is of primary importance to TIG operation with HF since it prevents the HF pulse from climbing through the internal circuits of the power source damaging other parts Thus during various maintenance operations make sure that this board is always firmly connected to the original terminals before activating HF start up The mains voltage again at 230 Vac to power the service transformer 4 combined with the fuse board 4 is drawn from the terminal board 52 This transformer provides both the supply voltages needed by the various sections of the control board 40 and the synchronization signal of the pulse generators on control board 40 This is why it is important to match the polarity of the connections for both the primary circuit of
39. st also be closed If incorrect replace control board 40 3 302 221 15 01 07 CEBORA S p A 26 4 COMPONENTS LIST 4 1 Power source art 236 76 see file ESP236 76 pdf enclosed at the end of the manual 4 2 Components table see file ESP236 76 pdf enclosed at the end of the manual 4 3 Spare parts list Essential spare parts Ref Code Description Qty 4 5610097 service transformer 1 40 5602293 control circuit 1 42 5602290 HF circuit 1 47 5605539 thyristor group 1 48 5602289 shut off circuit 1 Recommended spare parts Ref Code Description Qty 5 5710307 current transducer 19 3200030 diode group 1 3 302 221 15 01 07 CEBORA S p A 27 5 ELECTRICAL DIAGRAMS 5 1 Power source art 236 76 see file SCHE236 76 pdf enclosed at the end of the manual 5 2 Waveforms Tek Arresta E 50 0 V m pa ooms Linea 7 0 00 V 50 0 V i l P 00ms Linea 0 0 15 50 00 13 50 00 5 2 1a 5 2 1b 5 2 1 Output voltage with open circuit power source par 3 3 7 Tek Arresta E ch RO y D TIT al ner TNT J eu v m i dye TEUER indir MS ORE ar SP T rd J 50 00 50 00 52 24 5 2 2b 5 2 0 Firing pulses for SCRI with open circuit power source par 3 3 7 Tek Arrestal E Tek Arrest 1 00 V n pa ooms Linea 7 0 00 V 1 00 V l pl4 goms Linea 0 00V 13 50 00 13 50 00 5 2 3a 5 2 3b 5 2 3 Firing pulses for
40. the switch 15 making sure the contacts close in the sequence shown in the table in the electrical diagram of par 5 1 Check mains voltage conditions 3 302 221 15 01 07 CEBORA S p A 11 CONTROL BOARD 40 POWER SUPPLY TEST a Control board 40 connector J2 terminals 1 and 2 16 Vac pulse generator synchronization signal for SCR1 SCR2 and SCR3 on control board 40 J3 terminals 2 4 1 16 0 16 Vac power supply to internal circuits of control board 40 J3 terminals 5 4 6 8 0 8 Vac power supply to microprocessor circuits on control board 40 J5 terminals 1 2 2 26 Vac start command circuit power supply J6 terminals 4 5 627 0 7 Vac pulse power source supply for SCR2 and SCR3 J6 terminals 1 2 7 Vac pulse power source supply for SCRI J8 terminals 1 2 2 30 Vac protection circuit power supply Check the wiring between J2 control board 40 and J4 fuse board 4 Check the wiring between J3 control board 40 and J1 fuse board 4 Check the wiring between J5 control board 40 and 26 Vac signal winding of the transformer 46 Check the wiring between J6 control board 40 and J2 fuse board 4 Check the wiring between J8 control board 40 and 30 Vac signal winding of the transformer 46 With power source off temporarily disconnect connectors J2 J3 J5 J6 and J8 on control board 40 and check the resistance on the following points of control board 4
41. withstand the maximum current of the power source The appropriate values are shown in the table Process Repuye ae Output current Output voltage Conditions resistance TIG DC 0 08 ohm 250 Adc fig 5 2 4a 20 Vdc fig 5 2 5a Start button pressed TIG AC 0 08 ohm 250 Aac fig 5 2 4b 20 Vac fig 5 2 5b Start button pressed OUTPUT VOLTAGE TEST ON RESISTIVE LOAD a Output terminals AB and AC of the power source values as shown in the table pm Regular operation SCR3 ENABLE TEST FOR AC OPERATION NOTE This signal is present only when the welding current is greater than approximately 50 Aac With lower currents this signal is absent and the SCR3 function is performed by just one of the two similar circuits on the shut off board 48 see NOTE in par 2 3 a Shut off board 48 connector J2 terminals 1 and 2 approximately 30 Vac Check the wiring between J2 shut off board 42 and J9 control board 40 With power source off temporarily disconnect connector J2 from shut off board 40 and check the resistance on terminals 1 and 2 of J2 on shut off board 48 Correct values approximately 300 ohm If in short circuit replace shut off 48 and control 40 boards If gt Mohm in all measurements circuit broken replace shut off board 48 Replace shut off 48 and control 40 boards 3 302 221 15 01 07 CEBORA S p A 23 SCR3 FIRING PULSE
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