My year old Primeweld sprung an air leak(s) so I opened it up and found this board with a burned resistor, can anyone tell me if this is normal? It seems to cut fine, I’ve also emailed primeweld.
Regards
-JR
PW just email me back, said this is normal.
yup it’s normal. its a ceramic coated resistor. It’s meant to act like a heatsink due to the resistor getting so hot.
No that is not normal. That need to be replaced before it burns complete up.
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George has forgotten more about plasma repairs and function than most of us will ever learn…
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As George said, that’s not normal no matter what PW support told you. At the very least it’s terrible circuit design. Overloading the resistor only works for awhile. Worse, it’s in the process of burning up and potentially frying the board. There’s a reason the parts don’t look like that coming out of the factory.
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I’m going to go with whatever George says. Plus as a guy who burnt his fair share of resisters up in school… That’s not normal. If it was a little yellow…ok but the blisters tell me there’s an issue!!!
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This does beg the question about WHY the resistor overheated. Maybe it was badly constructed and should be replaced for that reason, but there may be some other cause which won’t be solved with just a resistor replacement. Related to that, however, I would recommend mounting the resistor so that there is an air gap between it and the PCB. This helps cool the resistor and will keep your PCB from burning. At least 1/4" gap.
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I was told its the varnish put on the board burning off.
I agree it would be best if it’s raised off the board, or at least masked before they put the coating on.
If anyone else ends up open their case I’d like to know if theirs does look the same.
If that’s true then the burnt varnish will scrape off and you can check for cracks in the cement filling the resistor well. If that’s still solid then it should be ok. This resistor is just wire wound around a ceramic core. The only failure mode is the wire breaking due to mechanical failure due to over heating and would show up with cracked sealant.
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@CrazyCasey had this happen on a brand new machine. I think @nicaDd still has the machine and is still using it years later? It does look worse than the one Casey sent back.
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This is what mine looked like; February 15, 2023. Primeweld replaced my unit because I was having a Langmuir equipment caused interference issue that we (LS support and I) could not diagnose. @nicaDd has had my old machine and been cutting with it, without issue, ever since.
The thing about Primeweld is that they care about YOUR satisfaction so much, that if you push them on it, they would likely replace the machine, even though it works fine and this seems to be a common problem. That said, you have a 3 year warranty, I believe, so, if everything’s working, I’d say keep using it.
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Yeah, I’ll try to get time and open mine up and see what that resistor looks like. Mine has quite a few hours on it for a hobby machine.
I been meaning to open it and see how much metal dust has accumulated inside. I now people on here have said no need to filter the air being pulled in, but man, my fan is looking pretty dirty.
@CrazyCasey is alive! Who knew!
What value is it? I might have one for you.
I clean out all my plasma cutters and welders every month. This is the #1 reason I get them in for repair from metal dust shorting out components on boards. I also keep them covered with old towels and cloth covers when not in use. Never use plastic or rubber style covers as it will hold moisture in the unit.
Plasma cutter used for 6 months on a CNC table in for repair. Was not covered under warranty.
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Nice! Then there are those that were stored under the water table… 
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I dis-assembled my almost 5 year old PW Cut 60 this afternoon. My resistors are not bubbled. These are the only ones I could see that appeared similar to your image. Possible the PCB layout has changed.
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The resistor is on the front of the board that is under the board you posted. And your plasma cutter looks clean inside. 
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