no amp control... econotig..

[buk]

tech was awesome.. he has my welder and he is fixing it...
i should get it back monday..

[treflip]

That's good to hear Buk!

I am still working on understanding the board components and diagnosing the hardware. It's fun and I got a little 20mhz oscilloscope from Craigslist to help.

If it were on my priority list I would be further along but seeing as a new board is 400 bucks I'll stick to my slow-and-steady pace.

If I have the time to finish before I head out, I'll post the results. Otherwise it'll be awhile till I get to do it.

-Tre

[Ray W]

Wouldn't you know it. After letting my malfuntioning welder sit broken in the corner for the last 10 years, I now have need of it. I checked for info online after I just dropped of my Econotig at the distributor for repair. After seeing this thread, I suspect that this problem is not so uncommon and that the manufacturor *should* have a reasonable fix that does not include a transfer to them from my wallet of a large chunk of cash for an overpriced circuit board. Have any of the clever people here found the culprit component and been able to repair their welder?

Ray W

[treflip]

Not yet Ray, but $395 for a board keeps me plenty motivated!

I'm just about ready to list all the components and replace them one by one though. A lot of them are the same so it shouldn't take too long if I go that way. Either way I'll document everything and post it here to help anyone else out in my shoes.

[Ray W]

That would be great if you share what you find. Hopefully its a minor component.

Ray

[rahtreelimbs]

Any Word???

[iflybeech]

I'll be glad to look at some bad boards if anyone has them. I'm pretty good at reverse engineering stuff and have the tools to do it.
Dr. Bill UNC Charlotte

[treflip]

Haha, finally got some free time this christmas to relook at it. I came across this old thread! It seems like this is still a common problem so I'll resurrect it and hopefully have a good outcome in the end.

I did find a newer econotig on ebay for dirt cheap and have been using that for my odd jobs since then... been a little weary to post the board from the working into the old one just in case it's a little on the hardware side.

Anyways, I have replaced just about every component on the board with no avail but I'm going to try the rest of the components and hopefully find the solution.

The biggest problem I'm having is the board from this machine (KF788280-1995) is outdated and the newest service manual (TM-303J) is from 2008. Since then the board changed so that now the remote is regulated by the knob on the machine. The old board (mine) just gives full access to the range of current.

So there isn't a direct relationship between the two. I am currently going to school for electrical engineering but don't really know enough to make the relationship with a 100% certainty. The price of a new board ($450) is keeping me motivated though!

I said it before and forgot but I will continue to try to keep this post updated for those that get answers from the internet like me (the internet keep info for a long time and who really looks at the post dates anyways.. )

[cruizer]

A silly scope won't help much, really all you need is a Huntron tracker. You can test components in circuit and graphically analyze them.

[treflip]

Sounded good so I googled. The tracker is for smaller current ratings (60v @ .6mA) and the cost is a little too high for now. The board has a few components that are over this rating (thyristor and the IGBT) and might need to operate over the trackers range, but I'm not 100%.

I've posted the working board into the older machine and it works great so I know the board is bad. I tried looking at 3E services and they quoted me $275 to fix the board.

It's a $70 testing fee if they take a day or two to figure it out and then the rest if they can fix it. I'm thinking about it but need to wait until I have the money to choose it.

I wish I could find the older service manual though. That would make trouble shooting a little more straight forward. I will probably have to wait till this semester is over though to get back into it though.