Repair a circuit

Deep ends.

One technique is to scrape off the coating from the tracks on either side of the break, carefully tin them and solder a piece of tinner copper wire across to bridge the break.

Another is to find two soldered pads (probably the two nearest and either side of the break) and carefully join them by soldering a wire between these pads (insulated if necessary).

Another is to use silver-loaded paint and bridge the gap with that, after removing any insulating cover, etc. Typically used to bridge a break in a car window heating panel track.

Another is to get "circuit track" - copper foil strips in various widths with an adhesive backing, bridge the gap with this and solder to the original track (having removed the insulation).

Another is to use a very fine drill to pierce the board on either side of the break, put a circuit pin into each hole, remove the insulating film over the track and then solder the pins to a small piece of bridging wire.

Another is to replace the pins above with a single piece of wire that bridges the break and goes into each hole.

Another is..well you get the idea.

There are countless ways of doing this. Which method is best depends on things you haven't mentioned - one main one being why the break happened in the first place.

solder a wire around it

regards

Daveb

Thanks Sue and DaveB,

Dave, I may be able to solder a wire around it, but there's not much room inside a Palm Pilot.

Sue, to see why the break happened in the first place, see my post of Nov

28, Subject: I cut an etch on circuit board of Palm Pilot TungstenE. Help! The subject really says almost all of it. And I get the idea. Radio Shack/Circuit City should have one or more of the above products you suggest.

Does "Deep ends." mean it's a deep problem, or that deep wire connectors would help. :-)

You've given me some very helpful and reasonable solutions, since I know nothing about circuit boards.

I have learned though to: - not make even a small cut on a board with a box knife; - use an iron with a much smaller tip, and - maybe use an iron of less than 25W when working on boards (I'm not sure about this); - not use a soldering iron on a valuable circuit board (but I doubt I'll remember this one :-> ); - get a better magnifying glass;

Any further (constructive) suggestions, or help, would be appreciated. And if I were an electronics person reading my original posts, I'd think, "What an idiot!"

Dugie

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Getting to be an expert with a soldering iron is a great=20 idea - but I wouldn't recommend using anything expensive to=20 practice on!

Soldering a wire between pads is far less likely to make the=20 problem worse, by say shorting between tracks or lifting a=20 track off the board. In the UK you can buy stuff called=20 "Verowire" - it is very fine enamalled wire where the enamel=20 turns into flux as it is heated with a hot iron. That is=20 what I would use.

Deep ends was indeed a hint that this can turn into deep=20 doggie-doos. It is very easy to make the problem worse.=20 BTDTGTTS.

You might like to think about wandering into the electronics=20 faculty of your local uni and finding a technician to do it=20 for you. For the price of a few beers...

I think, from your headers, that you are a bit too far from=20 Dartmoor National Park, Devon UK, to suggest that you pop in=20 to see me and let me solder it for you, or even post it?=20 Mind you, I prefer Pimms..Good luck.

--=20 Sue

way back in the dark ages i used to repair pagers and HT's. when i encountered a broken trace like is being discussed i used to use "wire wrap" type wire. (wire wrapping was a common way to build one time projects and sometime was used in production electronics.) on larger traces (like from power supply) a piece of "solder wick" came in handy.

the other thing is the solder size. for traces as small as we are talking about standard gage wire is a bit too big. i had a spool of Ersen multicore that was as fine as a hair.

the right solder tip is helpful too. i used one that was necked down to a needle point.

then all it takes is a steady hand, nerves of steel, boundless patience, and some 5X or 10X magnifying goggles.

best of luck, Tim

More good suggestions, Tim. Many thanks to all who have offered help; you guys are generous and invaluable.

And I take it that a 25W iron is ok, and I have to "make" my own tip by filing it?

I didn't actually solder anything on the board, to avoid heat damage. Rather, melted a small bit of solder on the tip, then touched it to the loose contacts, so that it secured the joint. I also held the loose component in place while soldering (i.e. an on/off switch with 4 contacts, of which three were loose and thus I couldn't turn the Palm off, had to wait for it to time-out power-off). (Not to go into details. :-> )

Your Ersen multicore sounds good. I'm unsure of the solder type I use; it's in a clear plastic container, about 5cm h x 1.8cm diameter, with a hole in the cap's top for the solder to stick out. The solder is 1mm. May have no core, but it does emit fumes on heating. I lost the product description, but vaguely recall it as being for circuit work. I also just found I have another container with .07mm solder.

I may be able to recover that Palm. The main problem is determining which circuits were cut. :-( Sue's idea of visiting a local uni and finding a technician is wise good one.

Dugie

I think you mean "Reading". Pronounced "Redding". Unless you=20 mean Otis? Always been my favourite "soulman". Devon is=20 about 200 miles from Reading and about 200 years from Redding.

Your Uni technicians should be able to fix it - if they=20 can't, you could suggest to them that there is this nice=20 English female engineer looking for a job...

A bottle would do it. Two glasses and I fall asleep - what=20 is known across the pond as a "cheap date", IIUC.

It means I should have not tried to be clever.. it showed up=20 as "Palindrome" when I first invented it - before I knew not=20 to use UTF on usenet.. Based on Mony Python sketch "The=20 palindrome of Bolton would be Notlob"..well, it was funnier=20 when John Cleese said it. ;)

--=20 Sue

It shows as: "Palindr?me" with Thunderbird.

The very first palimdrome: "Madam I'm Adam". :-)

I'd recommend a 15W temperature-controlled iron. Some irons also have real iron plated tips, and if you use electrical copper-rich solder they will start to decay. I'd suggest either using a plain copper tip and filing it right down (although you can get 1/16" tips for the small 15W irons), or use an old trick with a bigger iron - clean it well and wrap some stiff bare copper wire around it tightly, leaving a stub sticking out, and then tin the wire. That effectively gives you a tiny bit which is also disposable. I've done a fair bit of tiny soldering and I think the key is to get everything ready mechanically, clean, in the right place, so all you have to do is apply the iron and then the solder (in that order!!) - keep the time to a minimum when you have anything hot. It's also worth considering whether the mechanical fixing of a broken component can be done separately from the electrical connection (glue, bridges, whatever)as it makes the whole job more solid.

One last thing, I should take out the battery. Modern stuff tends to be live all the time in parts, and relies on monitoring contacts for switching on & off. It's unlikely to be a fully isolating power switch.

Best of luck Bill

I'll look for and buy a 15W. These small circuit boards can't take much heat. My 25W heats to 750F, according to the Weller manual.

The tips I have are nickel-plated.

This old trick is amazing. :-) I'd almost do that rather than use 1/16" tips. Almost.

Is this a comment on my method of putting melted solder from the tip unto contacts on the board? I do know that it's not the correct way to solder, but it seemed to work, and seemed acceptable as a way to avoid ANY heat damage. Am I wrong?

Thanks. Sounds like a good idea.

The Palm is live from the Lith-Ion batt. The on/off switch, however, is now fixed and is/was working. Is it still good to remove the battery for other repairs? It's not difficult; the inconvenience is that they don't plug in like a well-made unit. They're soldered, so I'd cut the two wires, then reconnect with proper terminal connectors.

Thanks, Dugie

some types have assorted tips that can be obtained in various tempature ratings: i.e. 600,700,800 degrees.

pretty much. a small connection like this should take 3 seconds to solder: apply heat for one second, apply solder for one second, allow to flow for one second, remove heat.

applying the solder to the pencil as you describe will boil off the flux (rosen) which tends to result in a poor solder connection.

opening one wire should be sufficient.

New information for me. Thanks. :)

Thanks for the detailed instructions. 3 seconds seem a long time, but with a

15W iron, maybe not.

Even if it's a re-solder? I suppose so, since boiling off flux seems a bad thing to do.

Now that is obvious... once you mention it, Bill. Thank you.

Dugie

And as "Palindr?me" with Outlook Express.

Was it actually the first, or does it refer to the biblical first humans? :-)

Dugie

"Reading" pronounced as "Redding" isn't logical. The residents, however, know how their city's name is pronounced. :-)

If they don't know how to fix it, which is rather unlikely, I'll do that. Or should I suggest it anyway?

You understand correctly, and you would be appreciated here. ;-> And posting one bottle costs less than posting a case!

It's still funny, and unique. Why not use regular alphabetical letters, it would still work. And why not switch to Western European (ISO) encoding? It makes quote on reply much easier.

Dugie

If you keep on asking girls to change their name, one day you may strike out...;)

Oops. Too late, looks like I just struck out. :-) I really didn't ask you to change your name, did I? Not technically. And... I am now able to use normal quotes with your email, so one of my suggestions was good enough for you to follow, was it not? ;)

Dugie (hoping I'm not digging a deeper hole here)