Migatronic 385 problem

[sweetie]

Hello, so im using this welder about past three years and i was very happy with it, but yesterday when i turned it on:
1. The fan always comes on when turn on, this time it didnt come up.
2. The temperature indicator light was on, never ever that light wasnt on.
That welder i use only to weld my car, and the welder never experienced big temperature or any issues. So basically i turn it on, but that light is on, there is no fan and when you press button to weld nothing happens. Maybe someone has some clue what could be wrong? Thanks

 

[Country Joe]

Hi there, sweetie & welcome to the Forum!

I don't really have a clue, but I might be able to help with a few guesses!

First thoughts are that it sounds like it could be a problem with the thermal cut-out. But once that trips, the fan should normally keep running, to get it back down to it's operating temperature. so now I'm not so sure. Also, it sounds like you were just starting up, and you wouldn't expect it to cut out on a thermal trip if it's not yet hot, like at the start of a session.

Does the fan normally run from the moment you switch on?

Still the thermal cut-out seems the most likely cause right now.
I don't know where the thermal cut-out would be located on your welder, but I think they're usually located the aluminium heatsink that the rectifiers are mounted on or somewhere on the transformer.

If you do find it, I'd expect it to have continuity if it was still working, but be open circuit if it's not. You could bridge it's contacts to find out.

This is assuming the fan does work. If you can work out it's voltage, (most likely written on it) you could eliminate this, too - by giving it the voltage it wants, and seeing if it turns.

There will be other people who own/ have owned, or know a lot about Migatronics, so they may well chip in.
Could even be some kind of circuit that senses that the fan doesn't work, and creates a fault that stops you from welding without any thermal protection, so as to prevent any damage caused by overheating components?

I'm sure others will chime in with more (& better) ideas!

All the Best,
CJ

PS - Just seen, the fan normally runs from start-up!
Maybe test the fan first.

 

[sweetie]

thanks for welcome so im not a big expert in these things, i only weld and look for the mig to keep it very clean and do not overheat or something like that, and only thing that i have changed is spoil. last time i did turn it on was a week before and it was running perfectly without any kind a issue.
so yeah the fan is not turning on after i turn on the switch, but i was looking carefully whats inside and i found that thing who send information about temperature, and what i did was i heated it a little bit with heatgun and fan turned on to cool it down so i assume that the fan works, but something prevents it from starting at beginning.
And only thing what was different from the last time i was working with welder and yesterday when i turned it on was pretty cold nights in garage, about -10 degrees in Celsius , but i dont know if that can be bad.

 

[J.B. Welding]

I'm not familiar with your machine but does it need gas pressure to make the other services power up, and when the gas runs out does a light come on? The gas bottle may have emptied over time and with the cold the pressure will have dropped a bit. Just a simple thing to look at, good luck with the problem solving!

 

[sweetie]

no, no changes when gas bottle runs out. there is pressure and seems no probs with gas system. thx though