Re: Decapitated "eight"


l - you are right; there is an interupted trace. is there such a thing as conductive paint? if not i will use a low temp solder. this won't solve the other problems but it is a start. thanks - d


Hi, D.B.;

I'm glad you found the problem. About the conductive ink: yes, and the electronic components' suppliers usually have them. You'll find silver- and golden-foil conductive ink. I preffer the silver ones, but golden foil is told to be better. As I always tried them in small, low-current repair, I can only say the golden-foil (the one I have) does the job.

Just be carefull when "painting" the faulty trail; do not allow the ink to spread around, because you'll create new conductive path, and this is not what you want, right?

There is also the self-adherent cooper foil, mentioned a couple of times in here. It has a conductive ink and may be the best solution instead of the conductive ink. I was given a fairly piece for using in my calculators, and if I am no wrong, at you can contact them and ask for a sample, say, for teaching purposes.

Success, my friend. And best regards.

Luiz C. Vieira - Brazil


luiz; i'll try radio shack and if they don't have it there is a zac-kit near two of my favorite junk stores. if that fails i'll try begging or buying some of that copper foil. i have high hopes for this first fix but not much for the other two. i'll also try soaking it again in vinigar and blowing out the underside of thoes chips with compressed air. thanks again. - d


Hi, D.B.;

I hope you find anything close to you. Anyway, if you're not so fortunate and do not find anything, send me an e-mail (as you have my e-mail address) with your actual address and I'll send you a cut of the copper foil I have. Mine is a 25mm X 95 mm (about 1' X 3'¾); it's enough for repairs and for rebuilding some HP41 battery contacts. I'll share a cut if you need so.

Best regards and good luck.

Luiz C. Vieira


I was also given some chomerics copper adhesive laminate, by a nice person at this forum - Thank you, A.D. - it was more than I needed, so I sent some to other nice people.

I also sent a sample request to chomerics, by using a form in their web site. They shipped express international, a roll of many meters. Unfortunately I asked for a double sided adhesive - If you ask for a sample, don´t do the same mistake.

The address is, and the laminate is used for RF shielding. For keyboard repair purposes, I guess you´d better ask for the minimum cross-section copper laminate.


I do not like the adhesive coppers or conductive paints for making etch repairs. They tend to be very unreliable over time. I would recommend using solder.


Hi, David;

I read your post and I want to know your opinion about something.

Self-adherent copper foil tend to be unreliable in time, I can "see the picture". Can it be soldered in place? I thought about soldering the edges and make it a permanent fix. I kniow a piece of wire would do it, but it's hard to keep small pieces of wire while soldering them.

I was wondering about it: a small piece of self-adherent copper foil and a brief soldering on its edges. Would the adhesive cause problems? Or help? Say, if it melts and spreads around, that would be a problem.

Have you tried something like this?

Just a hunch. Any comments?

Luiz C. Vieira - Brazil


I would think soldering the self adhesive foil would be OK. I tend to put a blob of solder on each end of the gap in a bad trace. If it is a small gap, you can drag a solder bridge between them. For bigger gaps, I then take a piece of stripped wire wrap wire, tin the end with solder, and tack it to one end of the gap. Then run it to the other end of the gap, trim it to length, hold it down with a screw driver tip, and then mash it down into the solder blob with a soldering iron.

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