ESAB Migmaster Control Board

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Can I change out the resistor on R78 and possibly get the voltage control to work?ExcaliburLincoln Electric:Ranger GXT 250SA-200LN-25Pro MiG 256Pro Mig 180Esab CV 251Invertec 160Victor Torches”
Reply:What model migmaster?You can always try swapping it out and see what happens.  Worst case it burns out again.  If its like my Migmaster 251 taking the chance is a helluva lot cheaper than that board.  Might be worthwhile to upsize the resistor to something with a bit of a heatsink or higher wattage to try and keep it from happening again.
Reply:a resister will only smoke if something else is causing to much current to flow. overheating the resister. What is the full migmaster model name and the part number of the pcb.Send it to me by private message. I might be able to look more information up.You can always call ESAB tech support and ask them what might have caused the resister to burn up. Is the problem on or off the pcb. I looked in my file and couldn't find a pcb drawing that looked like your picture. 3 large plugs points to an older machine.
Reply:Innovat Corp is good at ESAB pcb repairs and reasonable prices. Had one done by then and referred a couple other members here to them.they also had good results.Typed on tablet using Swype. Pls excuse Swypo's(Typo's)Tiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:Thanks southpaw.   I'll check into Innovat CorpExcaliburLincoln Electric:Ranger GXT 250SA-200LN-25Pro MiG 256Pro Mig 180Esab CV 251Invertec 160Victor Torches”
Reply:Finally had a few minutes to spend on the 251.   After further investigation some advice from ccawg and a few You Tube videos on how to test SCR's,  I discovered a shorted SCR.   I have picked up a couple used ones on ebay since there seems to be none available in the free world until first of the year.   I need a set of (180RKI40) if any of you electrician dudes have a couple stashed away.ExcaliburLincoln Electric:Ranger GXT 250SA-200LN-25Pro MiG 256Pro Mig 180Esab CV 251Invertec 160Victor Torches”
Reply:http://www.irf.com/product-info/data...ata/181rki.pdfExcaliburLincoln Electric:Ranger GXT 250SA-200LN-25Pro MiG 256Pro Mig 180Esab CV 251Invertec 160Victor Torches”
Reply:[QUOTE=Excalibur;6352551]http://www.irf.com/product-info/data...ata/181rki.pdfI have the same problem. What value resistor is the one that burned up? Also was any other components bad? My issue is that I dont have any motor control also. Did you just change the resistor and it worked?
Reply:I had exactly the same problem, sent the board out to innovat and waiting for it to return. Also checked the main high amperage SCR's and one was bad. From the tech at innovat very common problem is the scr shorts the anode to gate internally and ya get the 40 volts backfeeding the gate circuit on the board and it takes out the resistor and an op amp lm324, wonder if a quick solution to this would be a diode that would block the backfeeding so no more bad scr's take out the board? If get mine working im definitely gonna try that potentail fix!!!