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Up Topic Welding Industry / General Welding Discussion / Dialarc 250 noise
- - By Bob seND Date 05-29-2008 03:37
My Dialarc 250 seems to be getting noisier.  On DC low setting there is a nice soft
hiss.  On DC high, there is a buzz and vibration that seems louder than it ever used to.
On AC high there has always been that AC noise, increasing as the amperage is raised.
That also seems louder now than it used to.  The machine seems to function normally
otherwise.  Is it likely an electrical problem, or is the machine just old, worn, with rattles
inside the case.  I'll open it up next week when I have more time to trouble shoot.
Thanks.  Bob seND
Parent - - By DaveBoyer (*****) Date 05-29-2008 04:30
There might be some fastners inside that have loosened up over time allowing things to vibrate.
Parent - - By sbcmweb (****) Date 05-29-2008 11:43
Try servicing the contactor as well. I had a few machines literally given to me because the contactor had started getting noisy. It would be an obnoxious buzzing & clattering sound. There's a little piece of rubber behind the coil & if it wears away, or the contacts don't seat well anymore, it will make that noise. After cleaning it out thoroughly, resurfacing the points (MODERATE belt sanding works fine) & putting some contact grease on the points, check the back side of that coil that faces the mounting plate. Apply some layers of clean black tape & trim with a razor blade. You want it to tightly seat in front of that plate it sits in. If the slide holding the upper contacts is broken, that will cause the vibration to occur too. I had an SCP 200 that got gradually louder over time. It was intermittent, but started getting worse. That was the problem. It could be something else, but if it's what I'm thinking, that may be it.

Like Dave said, check your connections inside & take a good look at the obvious before determining that it's junk. Not saying you're ingorant, I've overlooked MANY a simple problem in my great wisdom (haha)  before sitting down & going thru the simple stuff first. If you do need a contactor, any 2-3 pole 90 amp 115 VAC coil contactor will work just fine. I think I even have one for it. Ebay is the best place to get one cheap. I've purchased new ones for under $30. That's a great machine & had little issues with a good track record over about the 3 decades that Miller built them.

If that's not the problem, I just blabbed a bunch of nothing. My wife says that's about all I do anyways.

You could always sell it to me for cheap too! (haha) Good luck with it! Steve.
Parent - By MDG Custom Weld (***) Date 05-29-2008 13:05
Good post Steve.
I have a 1980's Hobart that made the same type of noise.  Ended up being the main contactor and the springs that pull the contacts in were getting weak causing the contact itself to "chatter" and "buzzzzz".  After a period of time running it like that, the contactor finally gave out and cost $150 to replace.  It's a real easy thing to replace if you have a basic understanding and can re-connect the wires in the same fashion they are removed.
Parent - - By 357max (***) Date 05-29-2008 14:20
The Dialarc does not have a contactor. Disconnect the input/primary power, remove the covers. Check the connections of the weld output. If you have the older twist jack plugs; check that the receptacles are tight and not shorting to the chassis. A common problem on older Dialarcs. If the out put receptacles are tight; check if the wood wedges are loose. These wedges tighten the coils to minimize the vibrations the core laminations make. Just tap the wedges tighter. Use a hard wood block and hammer on it like a punch. Don't hammer on the wedges.
Parent - By sbcmweb (****) Date 05-29-2008 21:40
I was assuming we were talking about the Dialarc HF. That's what I thought anyways. I guess I had it on the brain for some reason. A lot of people call that machine a Dialarc 250 too, myself included sometimes. DUH! Good info on the stick machine though. I learn something new every day! Thanks!! S.W.

"If you can't fix it with the biggest hammer you have....Call a friend & see if he has a bigger one."
Parent - By KSellon (****) Date 05-29-2008 21:42 Edited 05-29-2008 21:47
failure of diodes can cause buzzing or just loose windings inthe xformer

http://millerwelds.com/om/o314v_mil.pdf

No contactor in this unit.
Parent - By ESC300 (**) Date 06-03-2008 03:21
Mine had broken spot welds on the xformer-miller repaired weld-no noise
Up Topic Welding Industry / General Welding Discussion / Dialarc 250 noise

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