TIGWave 250 Troubleshooting

[G-ManBart]

Hey all,

Long story short, I have two Hobart TIGWave 250 welders and one is broken (got it that way). The good machine welds beautifully and has no issues. The second machine trips the circuit breaker instantly when you flip the power switch regardless of the range setting on the front. I pulled the wrapper, vacuumed the cobwebs out, verified the jumper links are in the proper orientation, etc and then looked it over pretty carefully. Nothing stands out in an obvious way.

It's nice cosmetically and all the boards look good, so at the very least it would be a good parts donor, but if it can be made to run that would be even better. I'm not out anything if it can't be repaired, but figured it was worth a shot.

Any idea what to look at??? I'm reasonably handy with a multimeter, and thought having a working unit would help, but I don't feel like spending $50 or so for a manual now that ESAB seems to have removed them from their website...so I'm sort of flying blind.

[ccawgc]

Call hobart or go to their web site and put in a request for a manual. email is free, hard copy is 15 dollars.
When Hobart was split ITW Hobart got all the manuals and they had them scanned.
To start trouble shooting. You need to check and see if any of the weld diodes are shorted. For first tests nothing needs to be disconnected. First test use multi meter is diode test mode. Read diodes both ways. One should be OL or very high. the other 0.200 to 0.700 SCRs should read OL both ways. If nothing stands out as a problem. try finding the transformer leads to the diodes and disconnect them. Then try powering up the welder. if breaker still trips transformer is bad. If power stays on then problem is in diodes / SCRs Or something between the diodes and the weld terminals.

[G-ManBart]

Call hobart or go to their web site and put in a request for a manual. email is free, hard copy is 15 dollars.
When Hobart was split ITW Hobart got all the manuals and they had them scanned.
To start trouble shooting. You need to check and see if any of the weld diodes are shorted. For first tests nothing needs to be disconnected. First test use multi meter is diode test mode. Read diodes both ways. One should be OL or very high. the other 0.200 to 0.700 SCRs should read OL both ways. If nothing stands out as a problem. try finding the transformer leads to the diodes and disconnect them. Then try powering up the welder. if breaker still trips transformer is bad. If power stays on then problem is in diodes / SCRs Or something between the diodes and the weld terminals.

Thanks, that helped a lot! Turns out it was an interesting day as far as these welders go.

I checked the diodes and they all read the same OL in one direction and around .445 in the other direction. The SCRs were both OL in both directions. At that point I disconnected the transformer leads to the diodes and she powered up fine. I reconnected the transformer leads to the diodes and then followed the cabling from the diodes to the rotary switch that controls AC/DC Neg/DC Pos and had an idea. I disconnected the power lead to that switch, and the welder powered up fine again so I was confident the problem had been narrowed down to somewhere between the switch and the output terminals. Then I realized I had never tried powering up the welder with that switch in all the different positions, so I did that.

It powers up and welds fine in AC and DC Negative, but trips the breaker in DC Positive. I welded some aluminum on AC with it running at 250 amps or so and then DC Neg on some fairly thick mild steel....no problems at all.

Not fifteen minutes after I narrowed the problem down to the DC Pos side a buddy of mine called. He had seen the welders when I got them, and tried the good one....just fell in love with it. He called to see if I wanted to sell them, and figured the bad one was at least good for parts, but now wants to try fixing it. I don't know if that switch could be the culprit, and if so whether it can be fixed or replaced, but he'll have to good one to take measurements off if needed. I broke even, he's got a welder he really likes, and hopefully the second one can be fixed 100%.

I did contact Hobart and will try getting a manual for my buddy. I'm just glad the bad one isn't going in the scrap pile!

[ccawgc]

Have him check the wiring to the polarity switch. Look for a diode that is switched in when the switch is in positive.
Or there may be a wire in the wrong place that causes a short.

[G-ManBart]

Have him check the wiring to the polarity switch. Look for a diode that is switched in when the switch is in positive.
Or there may be a wire in the wrong place that causes a short.

Will do....thanks!

I looked at the wires connecting to the polarity switch, and didn't notice anything obvious, then started testing continuity between the different lugs on the switch, but ran out of time as he wanted to come grab them immediately and I had to get the wrapper back on and buttoned up. It seems like it should be something that can be sorted out. Thanks again!