Big 40G Troubleshooting

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Hello all, I am in need of some help with a Miller big 40g serial # KB168555. I believe it to be a 1992 model year. I have no D/C output. I do have A/C on the slip rings. I am wondering if anyone has a step by step test procedure to troubleshoot this welder. I have the owners manual Miller sent me but they said they are not allowed to send the service manual out. I am not much good at reading wiring diagrams. Any help would be greatly appreciated.
Reply:

Originally Posted by Nap159

Hello all, I am in need of some help with a Miller big 40g serial # KB168555. I believe it to be a 1992 model year. I have no D/C output. I do have A/C on the slip rings. I am wondering if anyone has a step by step test procedure to troubleshoot this welder. I have the owners manual Miller sent me but they said they are not allowed to send the service manual out. I am not much good at reading wiring diagrams. Any help would be greatly appreciated.
Reply:Voltage at the rotor slip rings should be DC not AC.  PM me an email address and I can send you what troubleshooting info I have.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110

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Reply:Thank you in advance for any help I can get.Last edited by Nap159; 04-09-2022 at 08:26 PM.
Reply:Have you tried calling Miller's Engine drive customer service?  I had a similar problem and with a multi meter Miller walked me thru it over the phone.   It was a 10 amp slo-blow fuse and there rare as hens teeth.We've done so much, for so long, with so little. Were now qualified to do anything with nothing !
Reply:Well thank you guys for the help. I'm still not having any luck. I found the circuit board to be bad with no hope of replacement or having it fixed. Have any of you guys heard of converting one of these to the old rheostat system? It seems the only hope of saving this welder is converting it to "analog" controls from "digital". Again, thank you in advance for any help I can get.