Lincoln Squarewave 300....

Ive got one and Im thinking of selling it.

Machine is in good shape....however....!!

It works fine in AC in all features..but in DC mode..its all 300 amps output. It doesnt turn down. Full power all the time.

Ive had it for a few years in my To Fix pile, have used it occasionally when someone was using my Airco 300 square wave. Tigging in AC is not a big deal, even on steel for me.

Now I could sell it..or fix it..or have it fixed rather.....I swapped for it from a guy who claims he replaced all the boards and it still wont weld by the pot in DC. Ive got the docs from Lincoln

Is anyone interested in it, or should I try to sell it locally..or spend the bucks to get it fixed?

Its got full digital read outs yada yada....

This is what it looks like, but mine is gray...

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Anyone? California residents prefered...the critter is 500 lbs

There is cooler/chiller.

Frankly..i really really dont need it. Truely.

Make me an offer! Swap/ Trade!

Gunner Airco 300 Square Wave Airco 300 Square Wave (repair project) Airco 250 Squarewave (Esab) Lincoln Squarewave 300 Miller Dialarc 250 Danmig 240 Millermatic 35 Millermatic 35 with Cobra 400 feeder(aluminum) and Prince push/pull gun Lincoln Ranger 9 Miller 55G (engine being rebuilt as I type this) Hobart Bro. 85G (made 1943) Lincoln Weld Pack 100 Hobart 150 mig The current Democratic party has lost its ideological basis for existence.

- It is NOT fiscally responsible.

- It is NOT ethically honorable.

- It has started wars based on lies.

- It does not support the well-being of americans - only billionaires.

- It has suppresed constitutional guaranteed liberties.

- It has foisted a liar as president upon America.

- It has violated US national sovereignty in trade treaties.

- It has refused to enforce the national borders.

...It no longer has valid reasons to exist. Lorad474

Reply to
Gunner Asch
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There is a good chance it is a dirty Molex connector on one of the boards. Before doing anything else, I'd swing open the main panel and wiggle all the plastic connectors a bit loose and then push them back on firmly. If that doesn't fix it, then it may be a broken wire at one of the connectors for the pot or hand control. You might also try cycling all the panel switches a dozen times, they often get open contacts after sitting for a while.

If the current control works in AC, it seems like it ought to work in DC also, I THINK. But, maybe it uses different SCRs or something for AC and DC, although I doubt it. Probably there is a switch that tells the logic board which position the +/-/AC switch is in, maybe that isn't working right.


Reply to
Jon Elson

This is a squarewave, so it always rectifies and converts voltage, and then it either supplies DC, or inverts it to make square waves.

The bad connectors for inputs (pedal, pot on panel) would affect both DC and AC operation.

So, lack of current control in DC mode means something is bad in the small details of control logic, which is bad news to me. I think that some boards would end up needing to be swapped.

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