Electrical Fault ? - Kemppi Minarc evo 180

[Arx0007]

Hello. I have problem with my welding machine. It dosen't work any more. Only power light on switch turns on everything else black out. I opened it and everything first seems ok. But after little time one thing inside goes really hot. Is it impossible this thing cause all the problems? Sorry english its not my first language.

 

[eddie49]

Hello, and welcome to the Forum!

Is the machine still under warranty? If so, contact your supplier or the local Kemppi office. Defective inverter welders are not easy to fix, a DIY-solution is not likely. They are complex machines, crammed with a lot of electronics in a small area.
There is a service manual here:

KEMPPI MINARC EVO 150 SERVICE MANUAL Pdf Download

View and Download Kemppi Minarc Evo 150 service manual online. Minarc Evo 150 welding system pdf manual download. Also for: Minarc evo 180.

www.manualslib.com

The component that you have indicated may be a ferrite inductor. The reason for it getting hot is likely to be a short-circuit in another part, such as a power semiconductor, rather than this item itself being faulty.
There are some general troubleshooting suggestions in Post #3 of this thread:

WSME 200 Tig Fault No Power

My Tig has just stopped working . Can anyone advise please. The fan runs when I turn it on nothing else lights up . No display is in the Amps Readout . I’m wondering if the power supply has gone wrong . I can buy one on eBay I think . Just wondering if it might not this as the fan runs ? Some...

www.mig-welding.co.uk

I would suggest that you start with an initial visual check around the power semiconductors that are mounted under the finned heatsinks, looking for cracked components, burnt-through pins, and melted or lifted PCB tracks.

 

[Jan-DIY]

The part you highlighted is a current limiter for dc bus voltage.
Looks like igbt module is short.
Pita to desolder.
Fixed one in the past.

 

[Osku_84]

Hello guys!

I have three Kemppi Minarc evo 180
All have the same problem as the thread starter.

The warranty expired a few years ago.
Is there a general fault in the circuit board?

All of them also heat up those two parts (same as in the picture above)

I would be grateful if you had experience with the problem and replaced components

Best regards!
Osku from Finland

 

[Jan-DIY]

The problem is mostly in primary section.
Did a repair on a 150a unit.
Igbt short.
As usual zener also.

 

[eddie49]

Hello, welcome to the Forum, and Happy New Year !
As has already been mentioned, the reason that these components are getting hot is that the DC supply which runs the whole of the welder ( after rectification and smoothing of the incoming AC mains ) passes through them, and the current being drawn is too high. That is probably due to a short-circuit further inside the power section of the inverter.
When an inverter welder fails, it is often those high-power semiconductors ( IGBT or MOSFET transistors ) that break down. As such it could be called "wear and tear" or natural ageing. It could also be claimed as weak, under-specified or over-driven components, inadequate cooling, or poor circuit design....!
Depending on your experience in electronic troubleshooting and repair, and the price and availability of replacement power transistors, repair may be possible. With three faulty machines, it may be worth looking for help from a local electronics specialist.

 

[Osku_84]

Thanks friends!

I think the fault was caused by a bad generator
Happy New Year!
Thanks for your help!

 

[Osku_84]

The problem is mostly in primary section.
Did a repair on a 150a unit.
Igbt short.
As usual zener also.

View attachment 431144 View attachment 431145

Hi,
Do you remember the part number,
I would have 5 pieces 60APU04

I thought I'd change them and have a look

The parts are not very expensive

https://www.digikey.fi/en/htmldatasheets/production/118810/0/0/1/60epu04-60apu04

-Osku

 

[Jan-DIY]

Hi.
In this 150A unit G50N60HS Igbt were used.
Don’t know exactly what kind of diodes because they were not short.

 

[jprcabre]

El problema está principalmente en la sección primaria.
Hice una reparación en una unidad de 150a.
Igbt corto.
Como siempre Zener también.

View attachment 431144 View attachment 431145

hola buenas tardes cual es el Zener que también cambiaste?

 

[ionut_mtb]

Hello. I found this discussion when searching a way to repair my kemppi evo 180. My machine behavior: display turn on, i can adjust amperage but no output, after few seconds it turns off. >> those two components heats up - are ptc thermistors- used for protection, inline with power supply (when get hot, resistance changes and circuit cut the power). This are used for soft start the machine - for soft charging those big capacitors. After soft start, next step is that the relay near them should start and it will bypass those thermistors. Now full power goes to the capacitors. Each machine can have different problems. Symptoms are same but solution is different. You need to check step by step repair manual (service manual) posted above. > check shorted igbt, recrifier and then check voltages etc. in my case there is no short, voltages are good, but no output and relay that should bypass thermistors does not start. Also forgot to say that my fan does not receive voltage. When i did measurements i noticed something - if i start and then stop the machine (after 1-2seconds) the relay receive for short period of time power and engage, also the fan (but not every time - starts for one second).

The only way to check voltages was to start machine for 2-3 seconds - check voltage - and then close the switch. (Because to long time on it autoswitches off…)

I found that one diode next to the relay (with three pin - smd - looks like a transistor) was not good. Replaced with 1n4148 but the relay still not starting. The power stops next to the relay coil, where are 2 diodes. (If interested i will post also pictures).


I also want to measure the viper27 - to see if it switches in the main transformer (because i have no output…). Power supply at pin 1 and 2 is ok.

 

[ionut_mtb]

R42 was damage and also 2 diodes next to the relay. All ok now..

 

[randyweld74]

Hi @ eddie49 may ask you what is this 2diodes next to relay?bec. I have the same problem looks like both this diode is open when i checked and i want to replace it.thank you and God bless

 

[blacktheripper]

If i looked right : v23 and v16
I have problem with my evo 180, i did all manual checks and I'm not getting any voltage of measurement points, only main switch light turns on.

 

[Relic]

Be very careful when buying replacement transistors.
G50n60hs come in igbt and mosfet.
Don't try substituting the wrong type.
Use a mult-function tester to find a good transistor.
Check against replacement purchased.
This puts you on the right track.
Working on a welder at moment with these transistors.
Multiple have arrived and tested as mosfet, not igbt n-chanel.
Of note, diode on this unit are STTH60PO3SW.