reversing polarity on a Jasic MIG 200Y

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Hi,I have a Jasic 200 MIG inverter welder that I just can't get to run very well and even had decent welders try it to no avail.I have heard that reversing the polarity might do the trick but there's no obvious switch or way to do this so my question is is it possible by swapping around the 4 wires to the mains? Obviously one of the 4 currently goes to earth and I have always used that one for earth.FWIW I have tried different gases, brands of wire, different tip lengths, every possible adjustment, personal techniques etc and have had the machine for a few months now. Reversing the polarity is all I can think is left to do?Thanks much.
Reply:Take the cover off and follow the work lead to where it terminates. The lead for the gun should terminate near it. Swap these leads and the polarity is changed.I looked for the manual but didn't find it right off. You may search Youtube for a video on how to do it.
Reply:On my Lincoln the polarity is changed inside the door where the roll of wire is.
Reply:First, why are you switching polarity? What polarity is it on now and what polarity is the wire designed for?If it's on the correct polarity for the wire you are using, then you have a different problem.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:I had to change mine when going from flux core to solid wire so I assume that is what is going on here.GravelThe difference between theory and practice is that in theory there is no difference.
Reply:Originally Posted by GravelTake the cover off and follow the work lead to where it terminates. The lead for the gun should terminate near it. Swap these leads and the polarity is changed.
Reply:Has it ever ran well or is this a new problem?Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Originally Posted by MinnesotaDaveHas it ever ran well or is this a new problem?
Reply:Well that sucks man. The manual should tell you what polarity it was on as delivered. Then there will be a little diagram of what small change to make to switch it.In general:Gas shielded solid wire, DC+Self shielded flux core, DC-Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Volt meter will tell you what polarity it is. Like mentioned should be DCEP for solid wire, DCEN for T-11 or T-GS flux core. If it is already correct swapping to the wrong polarity isn't going to help anything."The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:Originally Posted by SandyVolt meter will tell you what polarity it is.
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Reply:Thanks for your "shot in the dark", appreciated and I'll chase that up more tomorrow.If the polarity isn't "feasible" then how is a switch from gas to flux core handled? Maybe I should try to get some flux core to try and if it welds good then that may be a pointer about the polarity.I am in Asia but I am a Westerner (Oz), standard 380V 3 phase here, pretty steady and reliable for this heavy industrial area, mains connection has no order, just 3 wires and one earth, should have taken a picture of that sorry. I have tried swapping the 3 wires around but doesn't make any difference. Oh and this is a different factory too, same issues at the other factory (not professional, I do my hobby things here). If no result soon I'm just going to buy a new one - with obvious polarity swap function! :lol:
Reply:Here is how to check your polarity:(open your wire drive wheel so it does not feed)Attach your leads to the tip and the clamp and pull the triggerThis one is clipped for DC- (DCEN) since it is running flux core.If I have it hooked this way and the voltage read out as negative, then the polarity would be for DC+ (DCEP) for solid wire.Bottom line, hook it for what you want to check, if the meter reads negative you know the machine polarity is reversed from what you wanted.Last edited by MinnesotaDave; 01-25-2014 at 10:04 AM.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Some of the earlier Harbor Freight units output was AC or switched polarity DC output which is going to look and taste like AC. This one could be the same. If so there is no manually switching polarity since the output is already doing that rapidly. Also if so, it isn't going to run either wire real well since the polarity will only be correct half of the time for either. That's my WAG somewhat influenced by that little faceplate logo in pics one and two that shows DC +-.. To me that might indicate that the output is both DC "plus" and "minus".. Again a voltmeter would help determine that too. For instance if you were to only measure (just picking numbers) about let's say 15 volts DC+ OCV when set on DC but  25-to-30 volts OCV when set on AC.Last edited by Sandy; 01-25-2014 at 12:36 PM."The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:Awesome guys, will give all your tips a go first up in the morning, time for sleep now!Thanks again for your efforts too, much appreciated, will report back what I find..... or pictures of my new machine!
Reply:There's pictures here of a similar Jasic MIG 200 model but the outputs are connected the reverse of yours.http://www.aliexpress.com/store/prod...764492098.html"USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:Well as you can see I swapped the polarity and was very bad ... (oh and the voltmeter went backwards)I went through everything again today, swap out mains wires, different gases (Ar and Co2) and flow rates, different stickout lengths, wire diameter settings, checked all connections internally and externally, don't know what else I can do.I had another person welding who is quite experienced while I changed wire speed and voltage and just could never get a nice "sizzle" sound, closest is about half speed of a "sizzle" that's more a serious of fast "pops" and sparks flying. Kind of like the wire speed is too slow or voltage too high but adjust to compensate and it simply doesn't work and you end up with normal wire too fast or voltage too low problems. Geez it's annoying.I have basically had enough and think it's time to call it quits and get a decent machine. Jasic might be generally decent but they aren't getting a 2nd chance with meLast edited by bexrbetter; 01-26-2014 at 04:22 AM.