Miller Thunderbolt XL shunt stuck.

Tue, 31 Aug 2021 10:05:50 GMT

go to see Welding Machine for Miller Thunderbolt XL shunt stuck.

New member with no welding experience. I just bought an unused Miller Thunderbolt XL that had been sitting in storage. Seller said the machine has to be on to adjust the amperage. Just want to check in with the board for advice on getting it to move. The plastic crank turns some but the shunt does not move. I don't want to strip the crank so I stopped. The grease on the shunt slides looks old and pasty. I haven't turned the shunt adjusting screws yet, wanted to wait for advice from the forum.
Reply:OK, first things first!  Get the serial number for the machine and go to the Miller website and down load the owners manual.  http://www.millerwelds.com/service/ownersmanuals.phpThe instructions for cleaning and lubricating the shunt block are in there.  Sounds like yours is pretty gummy and just needs a good cleaning.  Miller says to use no grease on the screw and I concur with that.  Grease will attract the dust and dirt further compounding the problem.  I do however clean the screws and rub them down with candle wax and then brush and blow the excess out of the threads.  As for adjusting amps?  On or Off does not make a difference.BTW, WELCOME to the show!RogerOld, Tired, and GRUMPYSalesman will call, Batteries not included, Assembly is required, and FREE ADVICE IS WORTH EXACTLY WHAT YOU PAY FOR IT!Dial Arc 250HFThunderbolt 225 AC/DCAssorted A/O torches
Reply:The seller is "misinformed". It does not have to be on to adjust the amperage. I am sure it is just stuck due to long storage. You are wise not to force it.Since you know what the shunt adjusting screws are, I gather you have read the manual and have looked inside the case. (You can download the manual from Miller if not.) I just cleaned up an old T-bolt last spring, so the following is from memory:With the case removed (welder unplugged, of course), blow out any dust with low-pressure air. Then,tap on the metal part of the shunt with a soft hammer while moving the crank back and forth. This should free it up. When it does, lubricate all the points shown in the manual with good-quality grease and move the shunt back and forth several times. Re-lube as necessary.If you need to loosen the shunt adjusting screws to free up the shunt, return them to their original position if possible. Then adjust as described in the manual.JohnOops! Rog02 posted while I was typing. Good luck with it.Last edited by Silicon-based; 09-02-2013 at 10:19 PM.A few weldersA lot of hammersA whole lot of C-clamps
Reply:Thanks for the replies.  I have the manual, just didn't see any detailed info on shunt cleaning. I like the plastic hammer idea, will try that. I don't want to change the factory settings of the shunt screws just yet. The screws appear to have some kind of Loctite on them, so it would be good if I can leave them where they are. If I can just get it to move I can clean the slides and re-grease.
Reply:I had to do the same thing with mine. Old grease was gummed up and could only get one rev on the crank. Works fine now, slicker n snot.