Kemppi Minarcmig Evo 200 - Auto settings jumping around

[T689]

My Kemppi Evo 200 mig welder is ace, love it and still works.

A problem has recently occurred though.

When on auto setting and changing the thickness of the parent metal, the thickness will suddenly jump with the smallest movement of the dial.

For example, 2.1mm moving dial slightly then jumps to 4.9mm, and also does similar when turning down the thickness.

I can get it eventually to where I want it, but does anyone know the cause of the jumping around is or what to do to repair?

 

[Pigeon_Droppings2]

Could be that the adjuster is busted...mine did it too. It's replaceable but needs to be soldered in...easy enough to do.

Seem to recall I bought the part online somewhere but my part number was discontinued so wasn't easy to find (my machine is 10+ years old!).

I can't remember what the part is...but it isn't just a potentiometer as I recall.

Is it still under warranty?

 

[500e]

Not not just a pot ?? do you mean a Log or Linear type wire wound ???

 

[Pigeon_Droppings2]

I think it's a linear step counter or something like that. I may have a pic somewhere.

You can tell it isn't a regular pot because you can just keep turning and turning.

 

[eddie49]

It will be a rotary encoder, producing a digital output as the shaft is rotated.

 

[Pigeon_Droppings2]

^^^what he said...encoder was the phrase!

Armed with that phrase I searched my emails and came up with...
ECW1J-ZZZ-SE0/076L BOURNS

But please check what you have to be 100% sure before ordering. It took me a while to find as I think it might be discontinued. If you get stuck you could swap the encoders...thickness is more critical than the fine trim I think.

 

[T689]

Is it still under warranty?

I think it’s about 8 years old, so no warranty.

 

[T689]

Thanks for all your replies everyone.

@Pigeon_Droppings2 - I would agree, thickness is definitely more critical than fine trim, I don’t even use the fine trim much, a great backup idea to swap the encoders.
Thanks for searching your emails and the info, I’ll have a look and will try a repair sometime as it is annoying!

 

[T689]

I have got round to taking the screen/board off the Evo200.

The number ECW1J-ZZZ-SE0/076L BOURNS (as Pigeon_Droppings2 thought) is correct, and is also the same part number used on the fine trim.

I have bought another Bourns encoder (ECW1J-R19-AC0024L) to fit and replace the redundant original (ECW1J-ZZZ-SE0/076L)

There is some damage to the ribbon cable connected to the board, suggesting this welder has been apart before I purchased 2nd hand, and probably pinched when casing put on.

Could this be anything to do with the issue?..
(I doubt it though as it was working fine and suddenly started playing up)

I'll check the ribbon cable with a multimeter tomorrow.

 

[TEO]

Please keep updating the fix as many of us on here have the same machine, I'm not looking forward to having to diagnose problems in the future, PCBs & electronics are way outside my comfort zone but watching your progress & then referring back will be a great help.
Cheers

 

[Pigeon_Droppings2]

Remember to refit the small plastic spacers under the encoder...otherwise the board won't fit right with the case....ask me how I know!

 

[T689]

Remember to refit the small plastic spacers under the encoder...otherwise the board won't fit right with the case....ask me how I know!

Thanks for the tip!

 

[T689]

Not the ribbon cable - continuity all good considering the visual physical damage.

Just awaiting arrival of new encoder & time to swap over.

 

[Pigeon_Droppings2]

Just take care when taking off the old one...I made a mess of it and had to patch the tracks .

 

[T689]

I have repaired & tested now.

All working good so can get back to welding, too long without it!!

For helping others - I can confirm the bourns encoder part number ECW1J-R19-AC0024L works brilliant as a replacement encoder.
The only thing is the length of the plastic 6mm control shaft is longer and needs trimming to match the length of old one, easily done before fitting to the PCB.

I also ripped the tracks, probably not putting enough heat into desoldering.

One other thing to note is when putting the cases back together, just beware of the ribbon cable from the display PCB - mine was pinched/damaged by someone before I had it, and have seen another on the forum that was pinched in the same spot, so keep an eye on this near the handle area upon reassembly.

Love this welder & chuffed to have it working as it should again!

 

[Tighobby]

Hi people, could anybody with this welder make a video of a running wire motor at different speeds with no wire to be pushed just motor on its own. Mine is not stable, motor brand new so that’s excluded.