250EX problems with foot pedal

Well, this is a problem that has been around for me for a while now. When using the foot pedal I can't get stable arc, nor can I feather it. If I push the pedal all the way it works fine, but as soon as I start backing off to about half way, it starts to arc. This is all while tig welding (DC).

So far I have replaced the 4053 chip, and then the entire mother board was sent to me by Everlast Canada, still no change. The new mother board made the welder run even worse. I have also confirmed that the foot pedal is working properly, and that the potentiometer has not continuity through the entire range.

Any suggestions? I have gone back to just using the switch on the tig torch, and that is just not right.

I also have an older (bought it 3years ago) 200EX that I use at home, never had a single issue with it.


Not sure if this anybody else has this issue.

See what value your potentiometer has.

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Originally Posted by performance

See what value your potentiometer has.

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Went over this with the distributor as well, it is the right pedal for the machine. I know the other models had different ranges, but this is the right pedal. I have had the machine for a about 1.5 years now, and it worked just fine for the first few months.


EDIT:

The foot pedal is 23k, and from what I understand it should be between 47k and 53k. I just went over my emails, sending this info to the distributor, and they never did get back to me on this. I am a bit confused though, since this is the same pedal I used when the machine was new, and it worked fine.

No, that would be the reason you are having issues. It sounds as if you have the wrong pedal. The foot pedal looks the same. Older models could have been accidentally sent out since they WERE identical without any external markings. Maybe Mike or Ray can chime in here.

200EX? Never seen one? The 200DX pedal will not work on the 250EX. 250EX should swing 0-50K (pins 3-4) and 50K-0 (pins 4-5). Also, 6 and 7 should have a short to let the welder know it look at pins 3-4-5 for the amp control.

So my best bet would be to get a new pedal then? Can I go to my local electronics store and puck up a 50k pot, install it and call it a day then? It sounds like a simple fix, and my background is in the electronics field, so I have done this countless times.

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Originally Posted by Boosted P

So my best bet would be to get a new pedal then? Can I go to my local electronics store and puck up a 50k pot, install it and call it a day then? It sounds like a simple fix, and my background is in the electronics field, so I have done this countless times.

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You can pickup a 47K pot and replace it yes if the pot it bad.

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Originally Posted by everlastsupport

You can pickup a 47K pot and replace it yes if the pot it bad.

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Well, it's not bad, but it is the wrong one (23k).


Thank you for the support.

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Originally Posted by everlastsupport

200EX? Never seen one? The 200DX pedal will not work on the 250EX. 250EX should swing 0-50K (pins 3-4) and 50K-0 (pins 4-5). Also, 6 and 7 should have a short to let the welder know it look at pins 3-4-5 for the amp control.

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Would these values and pin numbers be the same to check a 200DX pedal?

Is a 50k going to be a problem? I suspect that it is no big deal, but better to ask.

Should be OK, but 47K is a standard size.

200DX pedal is the one with the 22K inside. So sounds like the wrong pedal was shipped. In tech bulletins here we have a wiring diagram of the new pedal (250EX pedal)

So I finally got a replacement pot (50k vs 23k that was sent with the welder). Installed/soldered things up and put the pedal back together. Plugged it in and it worked perfect, no arcing issues, does not cut out…worked just perfect. I welded for about 5 minutes with it like this.

So, I went and put the cover back on to the welder itself as it was removed for the 4053 chip replacement. It was installed the entire time, just not screwed down. After the cover was put back on (with screws) I turned it on, and tried welding again.

Well, now things are even worse than before. I don’t know what is going on but this is very frustrating. I removed the cover from the welder again thinking a connector came loose or something..but could not find anything. It all looked fin. No electircal burn smells...nothing odd/visible. The high frequency circuit does not come on at all, with either the torch switch or the foot pedal (both working 5 minutes prior). The only way to get arc is to touch the work piece with the tungsten, and that is just momentary. I don’t think this is the 4053 chip, because there is no arc between the two high freq. posts at all.

The gas still comes on, and I can see/hear the LED’s and relays clicking on the main circuit board, but welding is not possible.

Any suggestions? I am not sure if all of the 250EX’s are just garbage or did I just get a lemon?

Boosted,

Look closely at the area around the vents in the right front.Your left if facing the machine. It iseasy it slice the wires leading to the Hf board if they get between the case(vent) and the edge of the board.
I can send you a picture if you can’t locate it.

Ray

Hang in there Boosted, after you get it fixed you will love it. Make sure its not in stick mode, after you get the high frequency working, turn the start amps to about 25 amps, that really helps to get a clean and positive start.

Ray,

I will check it out when I get to work tomorrow. I was just so frustrated that I just lef it alone, thinking it may be something simple I may have overlooked. Will post in the morning once I have a look at this area again. I am sure that I had a look over the entire board, thinking that it may be a pinched wire (to ground) but could not see anything. The problem was present even with the cover off though..

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Originally Posted by srp

Hang in there Boosted, after you get it fixed you will love it. Make sure its not in stick mode, after you get the high frequency working, turn the start amps to about 25 amps, that really helps to get a clean and positive start.

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Yeah, I know that when it does work, it works great. I have a 4 year old 200dx in my shop and lover it. I have not had a single issue with it, and it has never let me down. The 250EX has a few times, and I hope once this is resolved that it is smooth sailing.

Yea, you probably cut through one of the HF board wires when you put the cover back on. They lap over the side of the board (left side looking from the front). The board is mounted upside down, mid center towards the front of the machine on the left side.

I can assure you the 250EX is the cream of our analog TIG units, you're just have a run of bad luck.

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Originally Posted by everlastsupport

Yea, you probably cut through one of the HF board wires when you put the cover back on. They lap over the side of the board (left side looking from the front). The board is mounted upside down, mid center towards the front of the machine on the left side.

I can assure you the 250EX is the cream of our analog TIG units, you're just have a run of bad luck.

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After messing around with it for a bit longer I found the issue.

For some reason the "Pre Flow" knob was turned to about 5 seconds causing the start delay of the HF circuit. I never thought to look at that, and did not think to relate it to the actual "weld start" condition. It makes sense when you think about it, I just though of it as gas related only, and since I had gas flow did not think to mess with it.

Thanks for all the suport, really appreciate it.

Hope this is the last of any problems with this machine.

Also, has Everlast though about a filter kit for the cooling fan? I have been using compressed air to keep the inside clean (blowing it all out with the cover off), but a filter system would be much better.

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Originally Posted by Boosted P

Also, has Everlast though about a filter kit for the cooling fan? I have been using compressed air to keep the inside clean (blowing it all out with the cover off), but a filter system would be much better.

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Interesting point on this. The company I work for, we have cooling fans on some of the stuff we make/sell. It actually turned out to be more of a liability to have filters than to not have them.

Without them, things get dirty and not so pretty. But WITH filters, customers would forget about them and neglect them (especially mounted in a rack). They would get plugged and cut off air until stuff starting overheating.

Temperature causes exponentially increasing aging on electronic components, and it actually caused MORE failures than no filters at all.

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Originally Posted by Boosted P

After messing around with it for a bit longer I found the issue.

For some reason the "Pre Flow" knob was turned to about 5 seconds causing the start delay of the HF circuit. I never thought to look at that, and did not think to relate it to the actual "weld start" condition. It makes sense when you think about it, I just though of it as gas related only, and since I had gas flow did not think to mess with it.

Thanks for all the suport, really appreciate it.

Hope this is the last of any problems with this machine.

Also, has Everlast though about a filter kit for the cooling fan? I have been using compressed air to keep the inside clean (blowing it all out with the cover off), but a filter system would be much better.

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Just be careful to NOT get the nozzle too close to the boards when doing this. Sometimes the things attached to the boards aren't all that solid and compressed air can cause them to break loose.. Seen it happen before and it's almost impossible to figure out what all is damaged when that happens.. I use compressed air as well but I stay way back from the boards when doing that..

We use compressed air in a can for computers because will do not want to spray air compressor oil all over our electrical components and that too, not to blow chips out of the board. LOL

No worries, I have a lot of experience with electronics. It is easy to blow off surface mount resistors and capcaitors, but not the though hole components that Everlast uses. The air is oil/contaminant free as it is a food processing facility.