1980 Miller Dial Arc 250, Tripping Breaker At Start Up!!!

[seagiant]

Hi,
Tried to use my Miller today and it's tripping out on start up.

It is also making a hum, it never did before at start up then trips the 50 amp breaker.

Never had this problem before, also the cord to the outlet and the breaker are fine with my Mig 180, so...

I'm thinking I have a Welder problem?

Does anyone here have any ideas on this?

This Welder is a Beast and not looking forward to taking it to a shop, rather fix it myself, if possible!

Thanks!!!

[Bonzoo]

Killer rig. You need 60 amps for the breaker. Better to hardwire the thing

[Sparkie1957]

The hum and the tripping, my first thought is a rectifier diode. I could be way off but I would research that first


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[ccawgc]

check the weld diodes one might be shorted.

[Louie1961]

Killer rig. You need 60 amps for the breaker. Better to hardwire the thing

HOLY SH!T man, I've missed seeing you around here. Welcome back.

[MinnesotaDave]

Yep, I'm going with diodes too.

I popped one while welding once. Machines starts to hum like its fully loaded - dead short.

[seagiant]

Hi,
Thanks everyone, have not got it open yet but had no problem for years, now this.

I guess if I see nothing, (burnt?) then I will just have to test, all the diodes, and see, if one is bad with the Fluke VOM?

[Sparkie1957]

There is a diode test function on most Fluke meters. Download a manual from Fluke to get the process for checking them


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[seagiant]

There is a diode test function on most Fluke meters. Download a manual from Fluke to get the process for checking them


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Hi,
Thanks, I'll have to find them first, but downloaded the closest Owners Manual from Miller, so should be ok!

[seagiant]

Hi,
Ok, opened her up and found 4 Diodes, 2 of each goes to the same terminals...

Just nutted in on one end and then a wire going to the attachment point, looks easy enough to pull one at the time and test.

Did not see or smell any burning or something getting hot?

IF I do find a bad Diode, would you just buy and replace all of them while I'm in there???

[Sparkie1957]

I would suggest looking online, perhaps EBay. They don’t have to come in a Miller bag. There are threads on suitable replacements. I would change them all out


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[MinnesotaDave]

I agree, change all 4.
The cheapest cost diodes I've found were on ebay for the DC wind power projects.

Way cheaper than Miller.

[seagiant]

Hi,
Thanks, will look into that.

I labeled and tested all 4 diodes, one was bad, so I'm going to put in 4 more!

Thanks to everyone for the help so far!

[seagiant]

Hi,
Found these on EBAY, of course, I know, I need 2 pos and 2 neg polarity.

They do say these are for Miller Welders, just checking before ordering.

Is there a certain Diode you guys use???

https://www.ebay.com/itm/Part-037-30...4AAOSw33FfoCyY

https://www.ebay.com/itm/Part-037-30...YAAOSwEJdfoC0-

[seagiant]

Hi,
I E-Mailed the Seller on EBAY and he told me more about the Diodes as far as size ect.

Seems a decent company so I ordered 4 new Diodes for about $110...

That's what Miller wants for one almost.

Called Digi-Key and got the phone run around.

The Guy on E-Bay used the same numbers as Miller and there were really no question on if they would work...we will see!

[Sparkie1957]

Sounds like a good deal. You’ll have a great welder for many more years when those are installed


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[seagiant]

Sounds like a good deal. You’ll have a great welder for many more years when those are installed


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Hi,
Thanks for the help again, I was Merchant Marine for 40 years and the last 20 in the Engine Room.

Did a lot of repairs and fabricating...

Almost every ship I worked on had a big, 3 PH, Lincoln or Miller stick Welder, and with 3 PH and DC, you really had a smooth running machine.

Saw this Miller Dialarc 250 on CL for $325 and jumped on it.

Came with 50 ft. Leads a new Stinger and sat on a Miller OEM Iron Wheeled Cart.

Has worked fine for years, this is the only problem, but it is 40 years old, but...

She will burn a rod!

[Sparkie1957]

I had a Dialarc 250, I think it was a late 80’s. I restored it and having powder coated and had a custom aluminum diamond tread top bent for it. Great welder!



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[seagiant]

I had a Dialarc 250, I think it was a late 80’s. I restored it and having powder coated and had a custom aluminum diamond tread top bent for it. Great welder!



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Hi,
NICE!

I like that top, might have to look into that.

Those old OEM, Iron Wheel Carts, are the Bomb!!!

[seagiant]

Hi,
My Diodes came in, will put them in tomorrow...

Hope that cures my Welder, we will see!

[Sparkie1957]

Think positive! Then negative! Lol. I’m sure you will have a good welder when your done


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[G-ManBart]

Hi,
My Diodes came in, will put them in tomorrow...

Hope that cures my Welder, we will see!

Wow...color coding for current direction....awesome idea! That's way better than a tiny little arrow printed on the side. You may already know this, but you don't want to forget the thermal paste between the diode and where it mounts. It helps the diode dissipate heat better and extends their life. It appears they had a couple of tubes of that in the package, so you should be set.

[seagiant]

Hi,
No, the paste was not included, I bought that earlier.

I labeled everything, so should be a snap!

[seagiant]

Hi,
Ha! Ha! Ha!...

Well, the new Diodes are in, and she's running, even more quite, than before...

All you can hear now is the fan running, and she's not tripping out, of course.

Admittedly, I don't stick weld everyday, but being able to use different electrodes makes this Miller more versatile than my Mig!

Thanks to everyone for the help and education, I now know more about Welders, than I really wanted to!!!

Happy, I was able to take care of it myself, of course!!!

Oh yea, I was wrong, they did include, a SMALL vial of heat paste!

[Louie1961]

[QUOTE=seagiant;8806731]Admittedly, I don't stick weld everyday, but being able to use different electrodes makes this Miller more versatile than my Mig!/QUOTE]

Well I might not go that far. A 250 amp MIG is WAY versatile than a 250 amp stick welder, in my opinion. Now if you are talking about a less powerful MIG, then it might be up for debate. ;-)