78 Black Face Trouble

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I need help with my 78 blackface i think its either the rheostat or the exciter shunts, i have auxilery power but when runnin the machine will only weld when fine current dial is set to 100 in any of the 5 current ranges i jus recently (2 days ago) bought the machine and only noticed the problem when i hooked up the leads and tried to weld the paperwork from the store i purchased it from said the shunts were replaced along with main brushes and 4-5 other things all the listed repairs are coverd under warranty through them for 30 days but im strapped for cash and need to get work so im lookin for any advice that could point me to the source of the problem any help would be greatly appreciated thanx
Reply:You have auxiliary power so the exciter is working.  What voltage is it putting out???  That the real question. lolMy other question might be "is it reving up?  If it's not then yea I can see it not welding at unless you're got it on 100.  (only a guess though).What is the engine RPM and what is the OCV?Without at least those numbers I'm not sure how anyone can help ya over the internet.  Good luck manLater
Reply:i have the right output at my terminals and according to weldmart all the right resistance measurements every they list to check but i did notice the rheostat isnt hooked up right according to their pics i have the blue wire in the center and the red runnin from the auxillery to the top terminal on the rheostat their site says this terminals not used the red wire supposed to go to the lower terminal but the terminal is broken off where the bolts supposed to go so where there should be a complete hole theres only half of one
Reply:and it goes from low idle to high idle when under load and back when not i flashed the field and checked the exciter field coil leads in resistance against the hot exciter brush and got 170 ohms on one and nothin on the other as specified then check against the rheostat and got 60 ohms ? im 22 years old and dont have much experience with mechanics but im tryin to learn lol so excuse my ignorance southern thunder had several posts sayin he had the exact same problem but never said how he fixed it and i dont know how to contact him through this forum (i barely figured out how to post these messages and start a thread ) lol any help is greatly appreciated thanx
Reply:can you get a picture of the rheostat?I had a rheostat that was broken at one point. It would not weld past that point.In my case, the rheostat had to be above 30. anything below that wouldn't weld.http://www.facebook.com/groups/sa200weldersCurrent machines:Hobart G600 Powered by 1967 Chrysler LH-318 (Project)Hobart GF-250(Traded)68 Redface81 Blackface