Bought a new to me Airco Dip/Stick 160 multiprocess welder

[H80N]

Guys I got bigger issues now, I put the old caps back in to double check and make sure everything was still working like before with the issue on high voltage. I had market all the capacitors so I knew which wayou they needed to go back in. I turned the machine on and hit the gun and sparks shot out. Now I have hardly any wire speed and a loud noise when I hit the trigger on the gun and I get a spark coming from what I think is a relay? The 3rd bar on the top left is making a spark when I depress the trigger I'm unsure where sparks originally shot across the floor from.

Here's a picture below. Hopefully something isn't ruined I can't seem to figure out what went wrong . The only thing I can think of is that I tried testing one of these ohmlite 50k resistors while still in circuit and it's causing my problem now.

The PIC you posted is the Contactor... how does it relate to your narrative....???

My first thought is that one or more of the caps were reinstalled backwads.... PLS check polarity...
a plus sign "+" and or a red dot indicates the positive terminal

[H80N]

FWIW... wrong polarity or AC may cause the Cap to "POP" separating the wound paper&foil innards and shooting it out of the can...in a dramatic display of smoke-paper-foil-and stink....

https://www.youtube.com/watch?v=3b7mjukhTyQ

those were little guys.... the large old ones can detonate in a truly spectacular fashion.....
(How Do I Know THIS..???..)

[Aeronca41]

Agree completely. The overheated metal is probably caused be almost a direct short somewhere, which a bad cap becomes for a while before it blows up. Sounds like there is a cap in backwards or caps are getting AC (bad or miswired diodes). Did you do anything with the diodes? Are your diodes all the same variety, with isolated mounting, or do you have two flavors, straight and reverse?

If either case is true, The caps WILL blow up and it will potentially be much more exciting than the little guys in the video H80N posted. Among other cases, I recall a power supply in a PDP11/45 memory drawer at Jacksonville Naval Air station where the wet shredded paper, plastic, and aluminum were packed in the drawer so tightly from the explosion we had to dig it out with screwdrivers-the vacuum cleaner wouldn't budge it. Amazingly, we cleaned it all up and salvaged the power supply. Bad diodes were the culprit in that case. There are AC Electrolytics but the normal ones do not like AC at all!

This is a tough break for you-hope we can get it figured out.

[Hondacivic247]

I get a spark at the contactor on the 3rd leg on the top when I hit the trigger.

I did mess with the diodes in the rectifier bridge but the only thing I did was test them. I have 2 on each side of the bridge and the metal rope coming off them both were bolted together along with another wire, I assumed it didn't matter which way I put the wires back on, or does it matter even tho there all on a single bolt?

I had marked all the caps to the bus bar so I knew which way they went back in. I also pulled the wires on the bus bars off to clean them but I only did one at a time to not get them mixed up.

[Hondacivic247]

Here's how they had the diodes on the bridge hooked up one bolt takes care of the 2 diodes on each side, and what I think is a wire that runs to those little orange caps? And resistor? In the middle of the bridge

[Hondacivic247]

[Hondacivic247]

[Hondacivic247]

I didn't mark each capacitors as to where they originally sat in the welder I just assumed sense there all the same they would go back in anywhere.

Imy going to pull all the caps and checking my markings to make sure they didn't flip flop the positive and negative from side to side.

I had marked 1 bus bar on each side with a + then each can with a + cause when I was taking it all apart you couldn't see if it was positive or negative until late it was out and cleaned off.


Is it possible that when I tried to test that ohmlite in circuit that it caused these problems?

[Hondacivic247]

I'm usually very good about makingk sure stuff gets put back together right and I have lots of pictures prior to me touching anything inside it and all looks correct

[Hondacivic247]

I pulled one of the bus bars on each side and just like I thought they were all hooked up correctly positive on one side then the jumper cable to the other on positive and all capacitors were correct.

The machine makes a terrible sound when you switch the polarity on the selector on the front. I'm praying one of the caps blew and that's my only problem, maybe the cap went bad from testing them?

[Aeronca41]

First, the order of the wires on the bolt is not a problem. As long as all are back on the same bolt it's OK.
--if you just used a DVM to check the caps, that would not have caused them to fail. Not to say you might not just have incredibly bad luck and one just failed on its own coincidentally. Doesn't seem likely.
--not sure what you mean by Ohmite? That's a brand name for resistors, thermistors, etc. don't know how you could damage those sorts of components with a DVM.
--Please verify you didn't unbolt any diodes-only removed the braided cable to test them.
--I see a black wire in the last pic that appears to be pulled tightly against a diode. That wire really should have gone around the other side of the diode so it's free of the diode. Be sure the insulation is good and it's not shorting against the diode.
--make sure that when you put the diode braided cables back together none of them is touching any metal anywhere other than the connecting bolt. The one in the last pic looks like it might be touching the upright end of the metal plate.

I've lost track is there a link to a manual with a diagram anywhere in this thread? I may have missed seeing it.

[Aeronca41]

Found the manual link. Missed it before.

[Hondacivic247]

[Hondacivic247]

I did unhook the braided cable for the diodes but there's only 1 bolt on each side that they both diodes on each side of the bridge connected to along with the smaller wire with the blue connector

[Hondacivic247]

I'll double check when I get home nothing is touching the metal and I'll double check all the diodes and make sure they still flow in one direction.