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Have HF but no ignition. HF arc unstable.

Posted: Wed Feb 15, 2023 3:51 am
by bebbetufs
Hello. I'm hoping someone can point me in the right direction.
I've tried the follwing.
Machine Everlast MTS 251si.
Chekced polarity
Adjustetd the HF points.
Moved the hoses and wires around.
Straightened the torch wire and moved it away from the + clamp wire to avoid HF leak to ground.
Preflow 1 sec.
Postflow 8 sec.
Cleaned and reground tungsten. (Type of tungsten is unkown but worked well with my previous ESAB Caddy Tig).
This gives a strong crisp HF sound and I can see the HF plasma forming. It is enough to dim my helmet.

To me it looks like the HF does not want to go to the work. It creates an unstable halo around the tungsten and sometimes jumps up into the cup. When it goes to the work it jumps far to the side, looking for imperfections on the surface on the work. The work has been cleaned with a wire wheel, but not wiped down (this hit me as I'm typing this).

The DC is present because the arc starts and is stable if I scratch the tungsten to the work when the HF is on.

Re: Have HF but no ignition. HF arc unstable.

Posted: Wed Feb 15, 2023 5:15 am
by Jack Ryan
It might be worth taking the torch apart and cleaning it. It looks like the HF finds a better path within the torch than to the work.

Jack

Re: Have HF but no ignition. HF arc unstable.

Posted: Wed Feb 15, 2023 11:29 am
by bebbetufs
Thanks. I'll take a close look later today.

Re: Have HF but no ignition. HF arc unstable.

Posted: Wed Feb 15, 2023 6:00 pm
by bebbetufs
I couldn't find anything wrong with the torch.
I ground the tungsten with a lesser angle which helped focus the HF arc to the work. I studied the HF plasma more closely and found that if the torch is too far away from the work the HF arc becomes unstable. I think this combined with a very pointy tungsten was the reason the HF arc was so unstable last time.

This time the arc was more focussed and it was quite obvious that the HF arc is very weak, barely a pinhead of plasma at the tip of the tungsten when the distance to the work is close. It seems I need to boost the HF somehow.

Re: Have HF but no ignition. HF arc unstable.

Posted: Wed Feb 15, 2023 7:58 pm
by Jack Ryan
bebbetufs wrote: Wed Feb 15, 2023 6:00 pm I couldn't find anything wrong with the torch.
I ground the tungsten with a lesser angle which helped focus the HF arc to the work. I studied the HF plasma more closely and found that if the torch is too far away from the work the HF arc becomes unstable. I think this combined with a very pointy tungsten was the reason the HF arc was so unstable last time.

This time the arc was more focussed and it was quite obvious that the HF arc is very weak, barely a pinhead of plasma at the tip of the tungsten when the distance to the work is close. It seems I need to boost the HF somehow.
I'm not familiar with your machine so I don't know what "normal" is. Have you had it for a while and it did work but now doesn't or is this it "out of the box"?

If you have to hols a very small tungsten gap to get an HF arc, it might be that the internal gap is still not right. Otherwise you need an Everlast comparison to see where "normal" is.

Jack

Re: Have HF but no ignition. HF arc unstable.

Posted: Thu Feb 16, 2023 12:07 pm
by bebbetufs
I appreciate your help.
I've had the machine since 2017, but only used the MIG function. As such I have nothing to compare the current situation to.

I got the gap setting from the manual. Is there a general direction to go to increase the size of the plasma spark? Bigger gap equals bigger spark?

I agree I would have to compare to another Everlast, but I live in Norway and there are not many of these machines here. I guess the best I can do is to observe that the spark is too weak/not working.

I got a reply from Everlast customer service, but they want $189+shipping + 25% VAT from the US for a new board. They seem to think it needs repair. I would like to repair it myself if possible as I find this very expensive. Especially since they only give a 30day warranty on new parts.

Re: Have HF but no ignition. HF arc unstable.

Posted: Thu Feb 16, 2023 7:53 pm
by Jack Ryan
bebbetufs wrote: Thu Feb 16, 2023 12:07 pm I appreciate your help.
I've had the machine since 2017, but only used the MIG function. As such I have nothing to compare the current situation to.
I don't think I can help much as I have never even seen an Everlast machine.
I got the gap setting from the manual. Is there a general direction to go to increase the size of the plasma spark? Bigger gap equals bigger spark?
There is an optimum gap/range that will give a good spark at a particular tungsten to work distance.

Did you need to change the gap by much when you adjusted it?
Did the adjustment make any observable difference?

I would experiment a bit - some would call it grasping for straws.
I agree I would have to compare to another Everlast, but I live in Norway and there are not many of these machines here. I guess the best I can do is to observe that the spark is too weak/not working.
I was hoping an Everlast owner might come up with some suggestions - one still might.
I got a reply from Everlast customer service, but they want $189+shipping + 25% VAT from the US for a new board. They seem to think it needs repair. I would like to repair it myself if possible as I find this very expensive. Especially since they only give a 30day warranty on new parts.
I feel your pain. The warranty period would have expired by the time you got the part.

Is there not a general welding service centre that could fix the board (or at least determine if it is broken)? I mean one that looks at the problem, not one that calls Everlast and orders a part - just in case.

Sorry, I'm not helping much.

Jack

Re: Have HF but no ignition. HF arc unstable.

Posted: Sat Feb 18, 2023 1:30 pm
by BillE.Dee
you stated that you haven't used the machine in some time (for TIG process). Check the manual and the connections are correct. Make certain that the correct buttons are pushed for the desired process. You will want to be kissy close to the material and make sure you have a good ground. I've found with my Everlast machine that the ground is finicky and the hf will have a hissy fit.