Omnipro 220 troubleshooting - help!

[htownnovice]

I've got an Omnipro 220 running super hot, regardless of settings.

Using the auto-generated parameters for a 3/32" 6013 rod (80A) and traveling at normal speed across 1/8" steel, the rod burned right through, cutting the steel in half like a plasma cutter. I tried turning down the current to the lowest possible setting (10A) and it did exactly the same thing.

Seems like there's a disconnect between the settings on the screen and the actual output of the machine: the output is maxed out all the time, even when the input parameters are reduced to minimal levels.

This happens with both stick and GMAW (I haven't tried MIG since the problem started).

What could cause this? I'm willing to try to troubleshoot the electronics if need be, though I'm no expert.

I tried emailing Harbor Freight's customer support, but, well, it's Harbor Freight.

I'm really regretting not buying that extended warranty...

Any ideas?

[jmmorriso]

Just a wild guess but maybe a stuck power transistor? Never seen inside one of those machines. I have tackled a couple cheapie machines in the past and won, but never a multiprocess machine. It could be that there is a communication fault, you'd need a more sophisticated electronics tool kit than I have to track it down. The boards probably talk with TTL or serial so you'd need a good scope to check that I think. Inverters are dangerous, like 600+ volts high frequency jumping out and frying people parts dangerous. Not trying to scare you, just don't know your experience level, and wouldn't want anyone I don't work with getting hurt. Some of my co-workers however...

Had to add that if it only happens in stick and tig that may be a clue since how constant current and constant voltage would be monitored and regulated differently, still just guessing. I like these puzzles though. I buy broken machines just to fix and learn. I'm not an electrical engineer, just a hobbyist.

[htownnovice]

Here's some more information about the problem. Check out this picture of the control screen:



The '10 A' is the current turned down as low as it will go. I never paid much attention to the number below it, because every time I looked at the machine it read '0 A'. Apparently this is the real time current to the stick, which only moves above 0A when you're actually welding (which is why I never say a value other than 0 A - I was busy welding).

Here we see a crazy high reading - 399 A - even when the current to the stick is turned off. If that's what's actually flowing to the stick when I'm welding, then it's no wonder it's so hot (instant and continued burn through, burning down the electrode extremely quickly).

In this video ( ) you can see the screen as he starts welding (at 7:55), and the actual current stays pretty close to the setting. Clearly that's not happening with my welder.

The question is: why is the actual current so high, when the setting is so low?

[ronsii]

I haven't used one or been around them... so can't really help with any firsthand knowledge... sorry...

But... first thing I would do is go through any and all troubleshooting stuff the manual offers if you haven't already then try to contact vulcan not HF for any kind of machine specific help and take some time to work your way through all the menus on settings and advanced settings... look for any resets or 'restore to default' options you can activate on the off chance this is some sort of software/firmware bug or glitch that got into one of the eeprom/ram memories... If this is some sort of electronic fault or bad chip issue then you're probably going to be SOL unless there is some chance you have more warranty then you think you have... bought with credit card that doubled your warranty??? or something similar???

One other thing to search out is a specific vulcan user group on the internet... as they may have more tech info as to chips and flashing memories if that's what the issue is... anyways good luck to you and hopefully you can get this sorted out and working again

Apparently there is a FB group... I don't FB so can't do anything more than this:---> https://www.facebook.com/groups/382997115472559/

[jmmorriso]

I'd guess it's not sensing current then. Current sensing on the weld output from what I've seen on welders is a hall effect sensor with a big wire going through the middle. I doubt the sensor itself is bad, probably whatever drives or monitors it's output since the display is reading almost double the amps the machine is rated at.

[htownnovice]

The welder is working again, for the moment. I opened it up and couldn't find any obvious problems. Blew out the dust (which was minimal) and put it back together again, and it's back to normal.

I was hoping to have something more useful to report in case anyone else has this problem, but oh well.

Main lesson I learned: buy the freakin' extended warranty!

Thanks to ronsii and jmmorriso for the help.

[ronsii]

Could be just a flakey connection between boards with multiwire connections.... any time things get computerized the slightest things can mess em' up ... and the slightest things can get em' running again

[jmmorriso]

Hey it works! That's good news, I'd call it a win. There could have been enough grinder shavings in there to bridge a couple traces and bugger up the works. Wish mine were all that easy!

[Louie1961]

I had the same problem on my Synchrowave once. Turned out to be a loose plug connection to the hall device.