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View Full Version : Brand new TIG box broke. Any suggestions?



Doc Nickel
03-12-2005, 12:11 AM
Just picked up a brand-new Lincoln Precision TIG 185 yesterday (Thursday.) Watched 'em uncrate it and unband it from the factory pallet.

Took it home and did some fooling around. Worked great on steel. Wasn't so great on aluminum- didn't "clean" well, seemed to take a lot more pedal than it should just to get a puddle going.

At the college class I'm taking, we have the big Lincoln 355 Squarewaves. If I set the amperage on 130 and stomp the pedal, I can melt right through about anything. On this 185, I had it set to the same 130, and had to stomp on the pedal just to sorta-kinda almost get a puddle going.

Had a helper watch the LED amperage readout while I welded- at full power (185 on the readout) and full stomp on the pedal, I got 90 amps.

However, it got worse as I fiddled more, eventually refusing to even start an arc unless I "scratch" started. And now, it emits a sort of buzz now, like when you stick weld with a buzzbox and "stick" the rod in the puddle.

I guess I'm going to have to load it back up in the truck and take it back, but I was wondering if anyone else had run across some problem like this, with this or a similar machine.

Doc.

Bill Neufeld
03-12-2005, 12:27 AM
Doc:
Got a few questions http://bbs.homeshopmachinist.net//biggrin.gifo you have a High freq start on the welder? When you were welding Al were you using Ac or DC? The Al welding done at work is done using AC not DC. Have you tried reversing the polarity of the welding current, assuming that you have a polarity reversing switch on the welder. I am more familiar with Miller CSW 300's and hobarts. If you have hf start is it still trying to start an arc? If you are getting HF; check that your welding cable has not burnt open.What kind of gas are you using? I'm sure the people with welding experience should be able to help you figure this out.
Bill

snowman
03-12-2005, 12:43 AM
Doc,

I'm sure you've already considered this...but
are you sure you have a good ground? Not only at the workpiece, but inside the machine. Maybe the little fingernut that connects the ground cable came loose.

-Jacob

torker
03-12-2005, 12:46 AM
Doc, it sounds like your hi freq might be hooped. I assume all is clean and you have a good ground connection through all the terminals. I had a problem with my HF start for a time and found out it was a bad ground. Hope you're that lucky!
Russ

rbjscott
03-12-2005, 01:01 AM
Make sure the machine is connected correctly internally.If the jumpers are connected for the wrong voltage power will be down. I made or did not catch this mistake. The machine welded great on thin metal, but heavy stuff and Al was a bust. Anyway took several months before I found the problem.

Doc Nickel
03-12-2005, 02:06 AM
Whoa, good replies for so late at night. http://bbs.homeshopmachinist.net//biggrin.gif

Okay, in no particular order: Machine's brand new, not even out of the crate two days. Dirt/gunk is unlikely to be the problem, unless it's swarf included from the factory.

Ground seemed to be okay- started out with it clamped to the table, later, as the problems progressed, I tried it clamped to the part itself. (Just alum. scrap I was playing with.)

Tried cleaning the aluminum better, wire brush, etc. No change.

The machine has no specific hi-freq selectable switch, but I assumed it has a built-in HF start. When I first tried it, it started the arc just fine, only towards the "end" did it start to not want to, er, start on it's own.

It also started without scratching even on the steel, so I'll assume it's HF start. (I have the manual here somewhere.)

And yes, tried Aluminum on AC, steel on DC straight, tried balling an electrode on DC+. All that worked just fine.

As for a problem with an internal connection, I took the top cover off and saw nothing obviously loose. There's more wires inside that thing than under the hood of a new Cadillac, so I didn't go randomly tweaking and yanking. But nothing was obviously loose or appeared missing.

The one real noteworthy problem is the main amperage dial on the faceplate. It has no stop. It just spins and spins and spins, and the readout on the LED screen doesn't always keep up with the knob. It might take five full turns to go from 5 amps to 185, but only two to return to 5. If you turn it slow, it'll take a quarter-turn to increase one amp, if you turn it fast it'll jump up, sometimes fifty, sometimes only ten, sometimes a hundred.

Obviously that's a problem, we'll see what they say at the shop tomorrow. (Fortunately they're open on Saturday.) Just curious if anyone else had a problem like this.

Doc.

3 Phase Lightbulb
03-12-2005, 03:10 AM
Keep us posted... I'm about to buy my first TIG machine too...

-3Ph

Doc Nickel
03-12-2005, 04:46 AM
Well, since it's a planned purchase, and I don't have a hot-schedule project waiting in the wings for it, and I know that every now and then you get a bum product for whatever reason, it's really not bothering me.

Which is a surprise, since I've been in a piss-poor mood lately. http://bbs.homeshopmachinist.net//biggrin.gif

I suspect it's nothing more than a bad circuit board. Behind the main panel on the welder is a board the size and complexity of a good PC motherboard, and who knows, a bad connection, one of a thousand tiny little components went bad, or it might be just the amperage pot itself is all.

Really, the worst part about it is that the shop, which carries both Lincoln and Miller, had to order the P-185 down from the city for me, which took the better part of a week.

If I decide to have this one replaced, it'll take another week. Again, no biggie, but still kind of annoying.

Or, I suspect I'll be able to swap it for the Miller counterpart, the Synchrowave 180SD. For the most part, the two are essentially identical, the differences being only minor features. The only reason I went with the Lincoln is I already have several Lincoln welders, and we use the big SquareWave 355s at the college classes.

I know they have a Miller on hand, I may just swap it out- I'm not necessarily "brand loyal".

Might have 'em run it in back and plug it in for a demo, first, though. http://bbs.homeshopmachinist.net//biggrin.gif

Doc.

IOWOLF
03-12-2005, 08:00 AM
Doc , I have the miller econo tig and it has 4 settings...AC 80 to 135, AC 30 to 90,DC +, DC-, my opinion is the first 2 settings are backwards should start out low the high, at first with my poor eyes I had it on the wrong setting, do you?

torker
03-12-2005, 08:14 AM
Doc....Whoa for sure! Geez sounds like you got a bit of a dog there. I have a shop full of red equipment and have never had a problem with it other than a minor problem with my plasma cutter. My 275 Squarewave sees a lot of use including air arcing and has never missed a beat. That being said, a buddy of mine was so impressed with my 275 that he bought one. He had nothing but trouble with it. He got so ticked off that he traded it in on an Esab. VERY nice machine! They all make duds from time to time. Good luck!
Russ

Tim Mehner
03-12-2005, 09:17 AM
I make no claims to know anything here, but I'd say your machine is whacked. We have some of the newer Lincoln's at work and they have the same issues with starting. They're the 275 and 375 models. Those things have never started correctly. We've had them worked on and still no change.
Also check to make sure the voltage is correect at the machine. I assume you have the correct size wire ran from the panel box to your plug/outlet? My Miller had 3 different voltage settings to choose from too. Just some wild guesses on my part. Good luck!

bob308
03-12-2005, 10:00 AM
al is weled ac continous hf . are you using the right tungsten?

J. R. Williams
03-12-2005, 11:19 AM
Doc
Check the input power connections. The unit may be set up for a higher voltage input than your supply. You said you were getting about 1/2 the power expected...

JRW

JRouche
03-12-2005, 12:41 PM
The way the problem progressed sounds like a faulty circuit. I would contact the distributor and have it replaced, not fixed. Lincoln is a good name so dont shy away from that, just a fluke. I have worked on electronics for 20 years and seen many faults that I thought, no way, this thing is brand new. But sure enough, new circuits can be bad too.

Whatever it is rely on the distributor, thats what you paid them for, markup on welding equipment is hugh. You should see all the different rates for various customers. Large profit margins allows for many customer rates.
JRouche