Yes, that can be fixed up, if that's what you're asking.

If it were mine, I would remove the cap and clean all carbon from the board using a fiberglass scratch brush before putting anything back. Even if capacitor tests fine, maybe not reuse it... it was subjected to an unknown amount of heat, which by its rating, lifespan is inversely proportional to operating temp.

Unknown (resized).jpeg

If you decide to reuse it, make sure its lead is thoroughly clean and takes solder. It certainly appears as if the original solder failed to bond to the capacitor lead, which caused a ton of arcing at this pad location. That alone may be a good enough reason to use a new cap.

Was it possible that you left this capacitor lead too long and just barely touching the trace above causing a short here?

Pinside_forum_7442392_1 (resized).jpg

Once carbon starts forming, it's just conductive enough to cause the problem to continue and get worse even after the original metal short melted away.

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If board traces are broken or lifted from the board, there are kits you can buy for epoxying the copper foil back down. Super glue does not work because any heat from soldering will cause it to release. I think I purchased some copper tracing foil from Marco last year. Otherwise, you can jump over broken traces by soldering solid copper wire across any gap. Yours does not look that bad, and may just clean up fine.

If the circular pad is missing or damaged, you can leave the capacitor lead extra long and bend it down along the good part of the trace; just solder it down flat.

Don't leave any copper traces exposed as shiny bare copper... either tin them with solder or paint them over with PCB mask.

You can use resistance mode on any kind of meter.

https://electrouniversity.com/how-to-test-a-capacitor-with-a-multimeter/

• Bad solder joint at the pad. It works until it doesn't. When it doesn't, you would get arcing and burning. The carbon is partially conductive so it contributes to the problem. Based on the photo, showing how the most intense burning was around the capacitor lead, I think this was it.

• Shorted to something nearby. The lead was left really close to another trace and eventually shorts out causing arcing and burning.

• Debris on left on the board was partially conductive or contained a contaminant that started a short that eventually causes arcing and burning.

That carbon is easy enough to remove... based on your photos, you don't need a new board. Also be sure to clean away all of your flux with alcohol after you complete any repairs.

Flux for electronics is generally not, but if it remains sticky, would attract dirt, solder balls*, etc. I like to clean it off, and if you're going to apply a protective solder masking, then you would have to clean it off. Removing the flux also ensures you won't leave general debris, solder balls, wire strands, etc. behind.

However, some flux is acidic and some containing solder/metal powders is conductive, so removing it would be a good "play-it-safe" habit in every case. Again, these types of fluxes are not typical since electronic flux is safe, not conductive, and non-acidic.

*Solder balls is a thing and can be a real problem. Molten solder falls and when it hits a surface, it splashes into a million tiny balls... it's like mercury. I've seen failures when examined under magnification, a tiny solder ball is stuck to something shorting out two traces. This is usually more of an issue on boards with tiny components and microprocessor legs so close together your eyes bleed when you try to focus.

I really like denatured alcohol because it's strong and dries quickly. However, you can use 70%, 91%, or 99% isopropyl as well. It just takes longer to dry. All of my Gottlieb work last summer, I just used 91% iso with a soft toothbrush. I got it in a bottle from the drug store with the plastic flip cap... so I could just squirt it out as needed.

Don't freak out when you have a divot or crater in your PCB after cleaning out all of the carbon. It's best to remove every last bit of carbon since it can cause these issues to come back. It's cosmetic; the PCB is only there as a physical structure to hold the conductors and components. As long as your components are secure and the proper electrical connections are solid and intact, you will be good.