PCB Repair or..?

Shadetreemonkey · Sat Jun 02, 2018 11:13 pm

Hey all, new to the forum. I’ll just say that I’m a still new to welding. I can only barely MIG weld... would love to start stick welding. Now, I’m not asking for tips, there’s plenty on this forum. However, I did not find what I was searching for. You see, I ordered an unbranded Arc DC welder on eBay. It’s an ARC-200 that supposedly runs on 110v with a max output of 200a, even has the standard US three prong plug. However, it arrived severely damaged. The seller gave me a full refund and did not ask for the welder back. So now I will attempt to fix it. Upon inspection, I found that the PCB was damaged. It has a broken corner. Could this be fixed? If so, how? The welder turns on but does not strike an arc. No sparks, nothing. The fan, knob, and output display work. But when I connect the leads and put the ground on the piece of metal, and an electrode on the other clamp, nothing. Not even when I touch the electrode to the ground clamp.I tried it on all output settings, even to the max of 200a. I am using Vulcan 7018 electrodes at 3/32. But I also tried the ones that came with the welder. I noticed the placard says the machine should run on 220v, could this be the problem? I feel that it should at least spark even with half the voltage, no? I used a multi meter and checked the machine. Both cables have continuity. There is continuity from the PCB both terminals, but I’m no electronics guy. Maybe the broken corner cuts off continuity where it actually counts? Is it the broken PCB or not enough voltage? Or both? How would I fix the PCB? Any suggestions will be appreciated. Thanks.

Mike Westbrook · Sun Jun 10, 2018 10:48 am

My thoughts would be if you got your money back look for a good used ac dc transformer machine the older ones use more power but are basically fool proof less parts = more reliable

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Demented · Sun Jun 10, 2018 11:38 am

Technically that can be fixed, but from the side shown, there's nothing there that would prevent it from working, so either there is other component damage on the top side of the board, or there's other things that would be preventing it from working. The soldering in some places looks really iffy to me though. Could be a good learning project if you want to get into PCB repair, but if it were me I'd toss it in my scrap board pile and pull components off of it to use for other things if nothing obvious stands out.

Can you post a full picture of both the top and bottom of the entire board?

Shadetreemonkey · Wed Jun 20, 2018 12:20 am

Sorry. Was quite busy.

Well guys, I reattached the corner to no avail. First time, so I might have done it completely wrong. Looking at it closer, I don't think that was the problem. That was a complete sheet of copper there. Not really what I think a trace would be. I just exposed about 1/4 inch of the copper on the board and the broken corner, then soldered two copper wires on it for good measure. Still does the same thing. Nothing when I touch metal. 7018s and the ones that came with it. Nothing at all. Still think it might be a 220v and the seller was just wrong. Don't really know for sure.

Welder · Wed Jun 20, 2018 3:39 pm

Hi, we can't help you if you don't give us more info on the machine. Post pics from all angles, information on the machine, manufacturer, etc. etc.

Look closely at the PCB, it may be multilayered one, but I doubt it. (multilayers are in between what you see, hard/impossible to repair.

Get a multimeter and take some measurements, do you even have voltage at the broken pad location? Take few measurements between this location and ground. Look around for solid state fuses (plain simple wire fuses, mounted in socket or soldered straight on the PCB.

I know some guys who are into power electronics and even some manufacturers of weldin equipment, I can ask around but I need more and detailed pics.

Edit: don't you have a 2nd phase (line as you say in the US) to test the machine on 220V??
I've heard that in the US every house has a second line coming into the breaker box, so you can actually use 220V!!!
(Line voltage between 2 phases = 220V.)

smithdoor · Wed Jun 20, 2018 3:52 pm

Shadetreemonkey wrote:Hey all, new to the forum. I’ll just say that I’m a still new to welding. I can only barely MIG weld... would love to start stick welding. Now, I’m not asking for tips, there’s plenty on this forum. However, I did not find what I was searching for. You see, I ordered an unbranded Arc DC welder on eBay. It’s an ARC-200 that supposedly runs on 110v with a max output of 200a, even has the standard US three prong plug. However, it arrived severely damaged. The seller gave me a full refund and did not ask for the welder back. So now I will attempt to fix it. Upon inspection, I found that the PCB was damaged. It has a broken corner. Could this be fixed? If so, how? The welder turns on but does not strike an arc. No sparks, nothing. The fan, knob, and output display work. But when I connect the leads and put the ground on the piece of metal, and an electrode on the other clamp, nothing. Not even when I touch the electrode to the ground clamp.I tried it on all output settings, even to the max of 200a. I am using Vulcan 7018 electrodes at 3/32. But I also tried the ones that came with the welder. I noticed the placard says the machine should run on 220v, could this be the problem? I feel that it should at least spark even with half the voltage, no? I used a multi meter and checked the machine. Both cables have continuity. There is continuity from the PCB both terminals, but I’m no electronics guy. Maybe the broken corner cuts off continuity where it actually counts? Is it the broken PCB or not enough voltage? Or both? How would I fix the PCB? Any suggestions will be appreciated. Thanks.

I only see one broken spot
I epoxy that corner
If any part of board copper broken just solder jumpers to fix

Dave

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Demented · Wed Jun 20, 2018 4:53 pm

There is a lot of crud on the board in that second picture, and the thru-hole IC is crooked as hell. Can't see any damaged components because of the angles of the pictures though. Second to last picture, the burnt looking solder blob on the bottom right. Is that attached to a component?

Shadetreemonkey · Wed Jun 20, 2018 8:42 pm

Look guys, you're getting a little to complicated for me. I'm a mechanic and blacksmith, not an electronics guy. Maybe I'm just way in over my head. It's an unbranded, Chinese welder from eBay. The rest of the info is on the placard in the picture. I don't know what pictures you guys want. I felt the pictures I took were adequate, but I guess not. That solder on the corner is the repair for the broken corner. There appears to be a heat sink behind that area. I don't know how to check power and continuity on a PCB. I only do that on cars. What I can say is that it turns on. I can hear the fan, I can adjust amperage as indicated on the analog display. Just no striking at all. No sparks even when touching electrodes to negative clamp. There are 220v outlets in my home, but the machine has a 110v plug. If I switch plugs, and on the off chance that it really is a 110v machine, then something will definitely give. I checked for continuity between both clamps while connected to the machine. There is none. There is continuity in the clamps themselves, from end to end. There problem seems to be that there is a break in the circuit between both positive and negative clamps when connected to machine.

Edit: I did notice that the through hole was crooked. The machine took quite a wallop during delivery right in the top. But it doesn't appear to be damaged. I guess it was just soldered that way... I need specifics. Exactly what info, what pictures, and where and how to test. I may not know PCBs, but I can follow directions. Also, it seems to be a single layer. Thank you for the help so far.

I tested the area of the repair and ground. There is no continuity. There also isn't any continuity between the positive or negative terminals to ground.

Mike Westbrook · Wed Jun 20, 2018 10:44 pm

I'm pretty sure it's 220 the sticker states the symbol for ac then 220 40-60 Hertz and I think 32.4 amps at full output of 200 amps if the large incoming brown and blue both goes to the on off switch then it's 220 you would switch both lines on 220 but on 110 you wouldn't switch the line and nuetral only the line or hot in most cases besides if that thing makes 200 amps on 110 it's magic

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Artie F. Emm · Wed Jun 20, 2018 11:01 pm

That machine absorbed a nasty shock in order for that board to break that way. Who knows, your solder connection may have fixed the board, but the impact shock may have damaged other vital components. Or, that machine may have been DOA before the board broke.

A repair technician would be able to tell you if the machine is "mostly dead" or "all dead" but that would cost time, money, and effort. The ebay seller refunded you, maybe it's time to get a different machine and weld?

Shadetreemonkey · Thu Jun 21, 2018 12:18 am

Mike Westbrook wrote:I'm pretty sure it's 220 the sticker states the symbol for ac then 220 40-60 Hertz and I think 32.4 amps at full output of 200 amps if the large incoming brown and blue both goes to the on off switch then it's 220 you would switch both lines on 220 but on 110 you wouldn't switch the line and nuetral only the line or hot in most cases besides if that thing makes 200 amps on 110 it's magic

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I thought the same when I saw the sticker. 200a from a 110v standard outlet would be magic. The blue and brown wires do indeed lead directly to the on/off switch. I wonder what would happen if I attached a dryer or RV plug to it?

Artie F. Emm wrote:That machine absorbed a nasty shock in order for that board to break that way. Who knows, your solder connection may have fixed the board, but the impact shock may have damaged other vital components. Or, that machine may have been DOA before the board broke.

A repair technician would be able to tell you if the machine is "mostly dead" or "all dead" but that would cost time, money, and effort. The ebay seller refunded you, maybe it's time to get a different machine and weld?

I think you're right. It would have to have been a heck of a wallop. The case was ridiculously caved in. I looked and I can't find any other obvious damage. Maybe it's damaged beyond what the eye can see? I hate giving up, but there's no point in saddling a dead horse. If I can't fix it myself for under like 30 bucks, then in my head might as well buy another one. I won it in an auction for 75 small ones, btw.

Shadetreemonkey · Thu Jun 21, 2018 2:45 am

Guys...

He is maudaa on eBay. Just something to consider if you ever do business with him.

Mike Westbrook · Thu Jun 21, 2018 7:21 am

Shadetreemonkey wrote:Guys...

He is maudaa on eBay. Just something to consider if you ever do business with him.

Simple mistake when they translated the chinglish

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Shadetreemonkey · Thu Jun 21, 2018 1:38 pm

He deliberately covered the 220v stamp with a 110v sticker...

Anyway. I'm guessing all I have to do is switch the power cord?

Demented · Thu Jun 21, 2018 4:51 pm

Shadetreemonkey wrote:He deliberately covered the 220v stamp with a 110v sticker...

Anyway. I'm guessing all I have to do is switch the power cord?

Possibly. It's already dickered so wont hurt anything if it goes pop if it's got components inside not rated for the 220v. Just make sure it's in a safe area before plugging it into 220v and that the wire is actually rated for it.

I've had some Chinesium machines from Alibaba before that had similar labels covering 220v stamps, but had 115v components inside.

Shadetreemonkey · Thu Jun 21, 2018 5:44 pm

Ah. Great to know. How would I be able to tell that the components are 220v? Well, what would keep it from creating an arc? Would insufficient voltage cause that? If not, then there's something else wrong and it might not be worth saving.

Demented · Thu Jun 21, 2018 5:58 pm

Could be insufficient voltage or it could also be other damaged components, or some other stuff. No real easy way to tell if the components are or are not rated for 220v. For $75, not really worth digging into it that much unless you want to do it for fun and learning.

Easiest thing to check was just if there were any obvious visuals of the factory installed blue smoke being let out or burns from shorts, but it didn't look like it.

Mike Westbrook · Thu Jun 21, 2018 8:20 pm

Put 220 to it on 110 the voltage returns so to speak on the nuetral side on 220 it switches + - on the two lines so if it's 220 one leg is dead but you could still be powering the 110 components fan dials display on the other line leg by pure luck when you drop a 220 volt load to 110 it's essentially at zero set it out in the yard run some cable grab a fire extinguisher and flip the switch !

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