My baby is sick!

admin

My thunderbolt a/c d/c 230 is bad off! I just got done laying my 3rd bead with a 7018, switched rods, went to strike up and bzzzzzz...... Sounded like my rod was stuck so I twist& pull butt it's not stuck, the loud buzz, like a direct ground still persists... I pulled the cables off the welder and it doesn't stop, so I flipped the switch.Tried it a few more times but every time the same thing... Loud buzz and the lights dim like it's at full output continuously weather at 230 amps or 30.!I unplugged the welder and took the shroud off, everything was warm but not hot, the wiring shows no burns or excessive heat, no grounded terminals or wires. After checking all the wiring for bad spots I turned it on with the shroud off.. The fan runs so it didn't overheat, but the coils tense up as soon as I turn it on.The diodes look ok at the rectifier but I have not tested them.  Could a bad diode or capacitor cause this?Not sure where to look from here? I'll put up pics shortly. It's a late 80s or early 90s modelReal welders know how to penetrate!(Equipment)Whatever can be used to beat my opponent into submission!
Reply:one or more shorted diodes could act like that.If you unhook the diode pack, that would tell the story.
Reply:Real welders know how to penetrate!(Equipment)Whatever can be used to beat my opponent into submission!
Reply:I'll unhook the diodes and see what happensReal welders know how to penetrate!(Equipment)Whatever can be used to beat my opponent into submission!
Reply:Sounds just like a popped diode.Same thing happened to me a few years ago - sounded like the machine was working at full power.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Yup! I unhooked the diodes connected to set strap running the low side ac coil and presto, no buzzing! So I did some more digging and found where the strap had made contact with the fan motor.Trouble shot one diode at a time until the bad one arc'd pretty good.! I will go ahead and buy new diodes for it and replace them all while I'm in there!I was hoping that was the problem, just needed someone to agree or say no way.Thanks guys!Also.. Dose anyone know a good source for 300v diodes or a kit for the thunderbolts? Online preferably, or should I just call miller..Real welders know how to penetrate!(Equipment)Whatever can be used to beat my opponent into submission!
Reply:Look up the part number in the manual and check miller4less.comGravelThe difference between theory and practice is that in theory there is no difference.
Reply:Will do. I've got a manual with the parts list in it!Real welders know how to penetrate!(Equipment)Whatever can be used to beat my opponent into submission!
Reply:I bought mine on ebay - there were lots of listings for diodes.Diodes were being sold cheap by wind energy people if I remember correctly.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Originally Posted by Dantheharleyman99Will do. I've got a manual with the parts list in it!
Reply:My brother blew the diodes in his thunderbolt by overheating.He was watching the duty cycle, but the welder was sitting on a metal flat bed semi trailer in the sun, while he used it.
Reply:Originally Posted by BlueweldersMy brother blew the diodes in his thunderbolt by overheating.He was watching the duty cycle, but the welder was sitting on a metal flat bed semi trailer in the sun, while he used it.
Reply:Originally Posted by BilldacatYou should replace the diodes in pairs...  The shorted diode puts a big stress on the one opposite to it.  IMHO: I would replace all four with a higher PIV and amp rated diodes and call it done.  Check out Mouser electronics.
Reply:Thanks for the link buildacat! I was planning to replace all the diodes and capacitors, that way I won't have to worry about them later..Real welders know how to penetrate!(Equipment)Whatever can be used to beat my opponent into submission!