Help repair elec circuit track?

[steveo3002]

I've got this rotten track where an internal batt leaked in a car alarm

Nothing to lose trying to fix it...looking for help is there any modern teqniques I could try or is it best to try a patch in a length of wire

 

[RonA]

I normally just solder a short length of thinish wire between end points, drop of glue in the middle if I want to make sure it doesn't move with vibration.
RonA

 

[Jonathan Webb]

What Ron said.

 

[steveo3002]

thanks not sure if i have a steady enough hand

is stuff like this a no no ? or worth a bash?

http://www.ebay.co.uk/itm/Silver-Co...691650?hash=item361a8d2502:g:78QAAOSwo4pYhKiw

 

[Seadog]

Stick with the wire. Use a fibreglass glass brush to clean the track and then tin it all before soldering in the wire. The silver paint is unnecessary. I used to use it repair DEC keyboards years ago when the silver track on a membrane wore through. Perfect for that job.

 

[gaz1]

your wasting your money that board just needs a clean up with a green brillo pad as I cant see any broken tracks from your pic other than some green joining into other joints

 

[Seadog]

Even if there are no broken tracks I would still tin them when clean, it'll protect them. That or some varnish, but you do need to remove all of the corrosion or it will carry on eating away until it causes a failure.

 

[steveo3002]

gaz theres deffinetly a chunk missing , it was quiet furry after the battery had leaked on it , internet suggested white vinegar to neutralise it? so ive scrubbed it in that and in fairness it did clean alot off , then ive started scraping at whats left

 

[rtbcomp]

If you want to solder say a 1/4" length of wire to a repair a PCB track, cut a 2" length and bend a 1/4" length at one end. The longer bit will be handle so you can hold it in place while the solder sets, this way you avoid dry joints.

Tin the wire and both ends of the track and put a blob of solder on the wire. Put it in place and melt the solder. Snip off the long bit.

I use fuse wire or tinned wire taken from some automotive-type stranded wire.

 

[voipio]

There's what looks like a surface mount capacitor near the top right of the board that still has a fair bit of corrosion-related material around and underneath it. Ideally all of that needs to be cleaned off, and make sure there are no deposits left between any of the copper tracks. If the deposits are conductive (they usually are, and tend to be more so when humidity is high) then the circuit will probably not work. Breaks in tracks can be tested with a multimeter set to measure resistance on the 200 ohms range, using the continuity beep, if the multimeter has one.

 

[pedrobedro]

Tin the ends of your wire and join them to the points that track connects. You don't need that steady a hand just push the tinned wire end down with the tip of the iron and it will flow itself in. You can add a bit more after if it looks weak.

 

[Bladevane]

If acid has leaked onto it then you need a mild alkali to chemically neutralise it - not more acid such as vinegar. Having done that I would then brush it with iso propyl alcohol to clean it before tinning or protecting as others have suggested.

 

[rtbcomp]

Tin the ends of your wire and join them to the points that track connects. You don't need that steady a hand just push the tinned wire end down with the tip of the iron and it will flow itself in. You can add a bit more after if it looks weak.

That can be tricky for a short length of wire, solder at both ends will be molten at the same time and it could stick to the soldering iron bit. A bit of aluminium rod can be used to hold the wire in place.

 

[steveo3002]

If acid has leaked onto it then you need a mild alkali to chemically neutralise it - not more acid such as vinegar. Having done that I would then brush it with iso propyl alcohol to clean it before tinning or protecting as others have suggested.

think the batterys are alkaline ? just going by the internet tells me

 

[wookie]

I've resurrected several dead computer motherboards where batteries have leaked and corroded tracks away, the first step is to use white vinegar to neutralise the leaked battery gumph.

 

[steveo3002]

I've resurrected several dead computer motherboards where batteries have leaked and corroded tracks away, the first step is to use white vinegar to neutralise the leaked battery gumph.

ive brushed it on with a paint brush , then gave it a scrub with more after a few mins trying to not drench it , will that be enough or does blue bits mean its still there

 

[wookie]

I wouldn't do it anymore than that, vinegar being acidic will eat away the copper tracks if left too long. You're aiming just to neutralise the chemical reaction of the leaked battery juice rather than use the vinegar to clean up the PCB.

A fibreglass pencil is a good tool to clean up the tracks enough so you can tin them.

After that it's usually time to solder on wire to bridge the gaps unless they are very small in which case you can just bridge them with solder. Try not to use too much heat or you may lift the track off the PCB completely (got that T-shirt )

The last thing to do that a lot of people don't bother with is to lacquer the board to protect it from tarnishing.

 

[HughF]

Send it my way if you don't feel steady enough... I'll do it for free just pay the shipping... standard day job stuff for me, got all the gear.

 

[daedalusminos]

This is what I'd do: Use a fibreglass pencil to remove all corrosion products from track back to bright copper, wick off dulled solder. Repair track by running and soldering tinned copper wire along, wrap round component pin at each end and solder. Tin all other 'cleaned' copper tracks and then thoroughly clean the board with IPA, allow to dry then conformal coat Electrolube SCC3

 

[fizzy]

In my student days a mate dropped his portable colour TV - they were pretty expensive then!
He asked me to fix it. All he had was electric guitar wire and a soldering iron with a tip like a spoon handle! I ended up using 40 jumpers to bridge the cracked board. Nobody was more astonished than me when it powered up first time. It worked for years after!
I see people mentioning fibre glass pencil. They are the spawn of the devil. The splinters get everywhere and hurt like hell.