conductive path cut (almost)

[kai]

I have a problem where most technicians just shy away from commenting so I would appreciate any thoughts. By accident I did cut into an audio amplifier pcie-cards' conductive path. It is kind of hard to tell from the attached photo but when looking straight from above you almost can't see the metal inside, only from a slight angle. I'm sure the trace isn't completely cut, but there might be some injury. If it still works is it also safe to be operated or are there any other considerations?
Thank you very much for any insight!

Edit: the damage is located in the left quarter of the image ...

[999999999]

Re: conductive path cut (almost)

Would it be possible to get a better picture or at least indicate on that pic where the cut is?


Whether it is a problem depends on whether it is only a signal or power trace, and how deep it is. Some people might call it a cut when all they really did is scrape away some of the coating on the trace. Is it definitely severed most of the way? If so, you'd take an x-acto knife or similar and scrape away enough coating on both sides of the trace to expose sufficient clean shiny copper to solder on a jumper wire. By jumper wire I mean I usually use something like transformer winding wire with the enamel coating removed or for higher current, the appropriate gauge of solid core bare wire with the ends flattened with pliers and bent down to provide a well mating contact to solder (not as beneficial until wire gauge gets down to about 22 gauge or lower).

Either way (including if it is not mostly severed), then clean flux and dust or sticker residue off the card in that area and cover the area with a small amount of epoxy.

Instead of the above, what you could do for now is just install the card and try it. If it works now, just cover the area with something thinner than epoxy like a single coat or two of clear nail polish so the copper doesn't oxidize, then if the trace were to fail later you can then solder on a jumper wire where the trace broke.

[Scenic]

Re: conductive path cut (almost)

If you mean that tiny chip into the trace on the left center, that's not even worth mentioning. Use it as it is and next time, be a bit more careful when removing labels for whatever reason.. lol

[kai]

Re: conductive path cut (almost)

Thanx to both of you for your thoughts. I attached another image, and although I didn't intend to hide the questionable spot it is kind of a relief to me that you didn't find it too obvious. This hardware isn't available anymore, that's why I am so concerned, and on top it is an audio part, so degraded functionality might not be easy to detect.
Plus I didn't just try to remove the label (that happened when removing some insulating tape) but was sawing the heatsink before I found that it's not glued (double lol)...
Anyway thank you once more for your input - I will try your advice!

[999999999]

Re: conductive path cut (almost)

lol, I thought that circled area was just a piece of the sticker. There is no need to do anything to it, that tiny nick will never matter.

[Jack Crow]

Re: conductive path cut (almost)

K,
Couple of tricks for next time, because there will be a next time.

Soak the sticker in solvent. Alcohol is good. It will take some time for the solvent to penetrate the paper, but after a while you can remove it w/o too much trouble.

Locate and use a glass brush.

Radio Shack has one.
http://www.radioshack.com/product/in...ductId=3998315
You can use it to remove the solder mask and not destroy the copper trace.

Just don't get the 'crumbs' in your skin or your eyes, you will be hating life.
That stuff will do awful things to flesh.

Jack Crow

[randtek]

Re: conductive path cut (almost)

Most labels can be cleanly and safely removed by heating with a hair dryer. No solvents needed.