This is the price you have to pay if you’re into real men’s hardware:
Being (falsely) identified as “old crap”, some cool things end up in the dumpsters… or worse. Being tossed around in some storage for years, probably stacked with other cards and boards, it might happen that some traces on the outer layers got badly scratched, thus making the board/card non-working. Here’s how I try to fix scartched traces… and most of the times it works:
First make sure that the circuit path (trace) is really broken – I just may look like, but isn’t.
To do this you need a volt-meter. Follow the suspected trace in both directions until you find a pin or through-hole it is connected to. Use these two points to test if the trace is still connected.
Ok, damn, it’s broken 🙁 You need three things:
- A sharp knife or scalpel
- Adhesive tape (Scotch, Tesa or whatever it’s called in your corner of the world)
- Conductive (silver) lacquer
Conductive-what? Conductive lacquer is actually a cool thing to play with… but be prepared: It’s not cheap (about 9-10 Euros). It comes in tiny bottles or as a pen, which is even more expensive (20+ Euros). The bottles look like this (lacquer and diluter):
Ok, the process is quite simple:
- Use the knife to scratch-off some of the coating lacquer on both ends where the trace was “cut” until you see some copper shining through.
- Check with your volt-meter that you actually have contact with one end and e.g. a pin on the other end of the trace. Do this for both “halves” of the cut trace.
- Mask the place you’re going to ‘heal’ with your adhesive tape – this prevents the conductive lacquer to run all over your board.
- Apply the conductive silver lacquer onto the spot you’ve just masked and let it dry (read the manual that came with the lacquer – yeah it’s unmanly but nobody will see you ;-))
- Using your volt-meter, check again. This time from both ends of the complete trace.
If you’ve done everything right, the trace should work again – and so does your card/board! Yay!
Here’s how my badly scatched MiroHIGHRISC looks like in certain places – can you spot the little silver dot?
Final hit: Some lacquers are quite thin on silver (blame the manufacturer) so after some days the spot you just fixed might become unreliable. In this case you might repeat the procedure to get more silver to that spot.