snap on welder

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I got a used snapon fm140a welder, needs some work one of the diodes is bad,Snap on want 75 dollar for one, is there somewere I could get diodes cheaper?180amp welder on 110VI am new to welding, so let me know if you need more info, The diodes in there say IN3290A  I not sure if these were the ones that came with,Some help would be great, Thanks
Reply:First off, can't help with the diodes.  How are you so sure it's the diodes in the first place?Second.  Someone sold you a "bill of goods" about that machine being a 180A welder operated on 120v power.  If it truly is 180A, then I hope you've got a 50A/125V service to run it.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:Do a Google search for Allied Electronics  or Newark Electronics. They are both great sources for electronic parts. You will likely get the best price from them. I buy mostly from Allied, but only because their warehouse is a bit closer and I can usually expect a 48 hour ground delivery from them. CharleyMiller MM252Miller Bobcat 225NTMiller DialArc HF / DIY Cooler2 Victor O/A TorchsetsMilwaukee 8" Metal SawMilwaukee Dry Cut "Chop" Saw 5 Ton Wallace Gantry Various Grinders, Benders, etc.
Reply:well its 180amp 100% duty cycle on 30 amp 110V cir,Well with the diode there are two, what amp and volt reating should they be?
Reply:LMAORIGHT.  That's some welder you've got there.  Defies the laws of electricity.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:Look at the spec sheet on snap on site FM140a ok its 140a my mistake,Anyway can someone explaine or help choose correct diodes for the welder,Can they be over sized? I guess I don't understand how they choose a certain diode,Thanks
Reply:The diodes need to be as high or higher in both amperage and voltage.The body and lead connections need to be approximately the same.Some diodes are body cathode and some are body anode.One of these might work,just check it out,:http://cgi.ebay.com/NEW-POSITIVE-Stu...item3cadd821ea
Reply:The specs for the diode can be found here: http://search.digikey.com/scripts/Dk...name=1N3290-NDThis is non-stock item for Digikey with a 40 piece minimum... so a quick google search found this place that has them for $15.http://www.ralphselectronics.com/Pro...er=SEMI-1N3290I would pull the diodes and check them with a meter, unless they are obviously toasted. Some meters have a diode check function. You might review this page for help:http://www.allaboutcircuits.com/vol_3/chpt_3/2.html
Reply:This is about the best forum responce I have every got from any forum, I will look into all that is sugested,with it being 140amp welder would 100 amp diodes be ok?there are two
Reply:Also I did pull them and check them one is open ether way
Reply:What effect will it have if I go from a diod that rated at 100 amp 300v to on thats rated at 150amp 800v?