Dan-Mig 140 Mono

[PoochonDad2020]

I recently found a Dan-Mig 140 welder on Facebook Marketplace for $40 usd and figured it was worth a shot. The seller purchased it with a lot of other tools/equipment at an estate sale. Anything that did not work with minor effort was to be sold. The seller said that the wire feed works on some settings, but the unit will not produce an arc. The unit seems to be extremely well built. I have not had a chance to power it up yet, but have started to do some research. From what I have read, this machine was built by Migatronic, and was sold in California back in the 80's. It was highly regarded by those in the auto body repair field.
I am a CCTV and access control systems tech at a local casino, and have always been an electronics hobbyist. I have a somewhat decent knowledge of power supply troubleshooting and repair, but by no means an expert.
Does anyone know of schematics, operating manual, or anything for this machine? A sales brochure, parts diagram, and price list were inside the wire spool cover. I will post scanned images of brochure later.
I figured there was a better chance of finding info from across the "pond"
Many Thanks in Advance!

 

[Robotstar5]

Welcome to the forum.

If you could post a pic of the welder we may have a better chance of recognising it and hopefully give you some info

 

[eddie49]

Here are photos of one that sold 5 years ago:
https://www.govdeals.com/?fa=Main.Item&itemid=362&acctid=7581
The data plate and the perforated steel side panel look very Migatronic.
I guess it will have the usual control circuitry, with a 24v DC auxiliary power supply and a small relay or a Triac on the PCB driving a large Contactor to power-up the main welding current. Check the coil voltage on the Contactor, and try closing it manually by pressing the plastic button in the top.

 

[PoochonDad2020]

Welcome to the forum.

If you could post a pic of the welder we may have a better chance of recognising it and hopefully give you some info

 

[PoochonDad2020]

Yes, it is definitely a Migatronic. I removed the control box to do a visual inspection of the board. No signs of pregnant caps. I have access to a Sencore LCR at work. If I remove them to test, its probably foolish to not replace them?

 

[eddie49]

That is a very impressive control panel! For $40 you got a real bargain; I'm sure we can get it running.
The controls of this Migatronic are marked with similar symbols and graphics:
https://www.mig-welding.co.uk/forum/threads/what-have-i-bought-migatronic-200-mono.47598/
Personally, I have never been inclined to replace caps just because they are old. I would start by locating the Contactor, checking that it can be operated manually, then powering it on and carefully ( with an insulated screwdriver ... ) pressing that operating button to see if it will feed wire and arc up.

 

[PoochonDad2020]

This control panel sure looks familiar. I attached a screenshot of the post the puc came from.
Thanks Eddie49. I'm going to make my extension cord from an old shore power cable from the old Pacemaker I cut up a few years ago and use the dryer outlet to power the welder and try the manual contactor test. I'll hit all of the pots with tune-o-lube (contact cleaner). God knows how long this machine was sitting.

 

[PoochonDad2020]

Well, here are the pics from the classified listing I found the welder on:

 

[a111r]

That's a nice quality machine!
Looking at all the crud inside, I'd first give it a damn good clean up and look for corroded connections on the selector and contactor.

 

[PoochonDad2020]

I finally was able to return to the Dan-Mig project, and this was the first issue I found:

No immediate evidence of anything fried on the control board. All of the fuses had continuity. I tried the manual contactor test, and felt and heard a hum. I tried again with the breaker in the panel turned off just in case it was a mechanical noise made by the spring in the contactor, etc. I didn't measure welding output voltage yet, but will tonight.
Another thing I noticed was no life in the wire feed motor. The seller had told me that the power light came on and that the wire feed worked when you pulled the trigger. I think he is full of it.
My theory is that there is no 24 volt supply going to the control board and feed motor, because the full wave bridge rectifier took a hit from the miswired plug. I hope to verify that as well this evening when I can get back to

 

[PoochonDad2020]

Of course, this testing was done after correcting the wiring at the plug

 

[PoochonDad2020]

Can someone tell me what the G5 terminal is on the rectifier? I am unable to find a data sheet for this online.

 

[PoochonDad2020]

Well, I went to verify the connection from the line cord to the machine, and found an open at the ground connection. Almost like it was a fusible link. Repaired that, and found one leg open from terminal block to contactor.
Put power to it and still no AC at rectifier on control box. I'm going to press on, and eventually close in on the problem. This thing really needs a deep cleaning (see pics)

 

[eddie49]

The Siemens rectifier ( ? , or dual rectifier, or solid-state relay ? ) "Thy DE11A13-B2 HKR" looks familiar. In fact, I saw one 2 weeks ago in Post #4 of this thread : https://www.mig-welding.co.uk/forum/threads/migatronic-325-compact.98786/#post-1508288
which is also a Migatronic welder. I too have not been able to find any data about this component.

I agree that your welder needs a good clean; many of the connecting wires look like they are corroded.

 

[Epace]

My unit looks similar, but it doesn't have all that control.
I found there are 14 pins on the blue connector on the back.
Pins are marked with letters.
One side of 24VAC goes to pins A and D, and the other goes to pins L and P.
DC NEG. goes from pins R and M, and DC POS. goes from pin C to the DC motor.
Pins F and E go to the torch switch.
Also the LP pins can close the circuit through the contactor coil through the TRIAK via pin H.
Pin B has POS. voltage with pins AD, as soon as the switch on the panel is turned on.
I hope this helps.

 

[Dennis Akehurst]

I also have a Dan Mig 140. Worked great till yesterday and then it just died, nothing when you pull the trigger. Power coming in but it does nothing. Any help for me??

 

[Darrell Dieringer]

Does anyone know of schematics, operating manual, or anything for this machine?

The OP asked for an Operating Manual. I just discovered this thread. I scanned the operating manual for my identical unit (Dan-Mig 140 Mono) and made the images into a PDF (sorry, no OCR). The file is too big to attach here, but it is available in my google drive...

https://drive.google.com/file/d/1bFf48E8ojOnmvtGjErFiWCAFZmt5AY0j/view?usp=sharing

 

[Darrell Dieringer]

I also have a Dan Mig 140. Worked great till yesterday and then it just died, nothing when you pull the trigger. Power coming in but it does nothing. Any help for me??

My Dan-Mig 140 Mono also died, mid project of course. I started a separate thread for that issue here...
https://www.mig-welding.co.uk/forum/threads/dan-mig-140-mono-suddenly-no-arc.104844/

 

[Jferguson]

By chance are any of your danmig 140mono parts machine now, I'm in need of wire feed motor?