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Does this capacitor look bad to you?

ShallowGrave

Feb 7, 2017
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Good evening,
I have been a lurker here for a bit and just recently had a problem I needed expert advice with. I am hoping some of you can chime in.
I recently inherited an older Hobart 250A Plasma Cutter that had its ground cable poorly replaced and was not functioning. After replacing all the torch consumables and replacing the grounding cable with a factory replacement and testing, all was not good.
All my attempts to talk to service agents haven't gone too well as it is an older machine and no one has a service manual for it. All indicators led to a bad PC board and I cannot for the life of me find a replacement. While digging around in the garage and trying (and failing) to clean, I picked the old cutter up and got curious. As a (brand new) Electrical Engineering student I couldn't help it.
What I found after a good inspection were these two capacitors. They aren't bulged, popped or leaking but obviously look different then they did from the factory. The plasma cutter functions normal until you try and cut. The pilot arc lights but will not transfer to a cut arc. If these look bad to anyone else, I think I may try and de-solder them and replace them. Replacement capacitors were very easy to find.
What do you all think? Worth the time to try?20170206_182728.jpg
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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Well... That discoloration on the end looks unusual.

Can you take a photo of the end of the caps that are discoloured?
 

ShallowGrave

Feb 7, 2017
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Feb 7, 2017
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Interesting find then.

https://www.electronicspoint.com/th...ace-mount-electrolytic-capacitors-smt.171721/

I will get the next photo as soon as I get off work. Though I don't recall seeing anything TOO obvious. In my impatience for, well anything really, I ordered two new identical capacitors this morning and i intend to pull those two and see what I can make them measure out with. I'll post what I learn.
THANKS FOR THE RESPONSES!!
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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Yeah, replacement seems to be the best option.

I thought it may have been a shadow, but after I looked in more detail, it clearly isn't.

I am curious if there are any other signs of leakage.
 

ShallowGrave

Feb 7, 2017
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I still can't see any bulging/cracking/or obvious leaking, though there MUST be something going on. This was as close as I could get the camera last night. After I get them removed I'll have the best view and if anything is revealed I'll add them here just for fun.
I cant hurt anything worse really since the thing doesn't work anyway, so here we go....
 

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davenn

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Sep 5, 2009
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I still can't see any bulging/cracking/or obvious leaking, though there MUST be something going on. This was as close as I could get the camera last night. After I get them removed I'll have the best view and if anything is revealed I'll add them here just for fun.

They look OK

I suspect the discolouring is lacquer that has been liberally applied to some of the board and parts
 

ShallowGrave

Feb 7, 2017
4
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Feb 7, 2017
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Well, for my education I will a least test them. I will continue to research other possibilities for the failure as well. Thank you.
 
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