• Hardware
  • Guide to repairing damaged PCB tracks.
2010/02/17 15:13:08
vlad01
After seeing what happen to Lonelystoner's mobo, I though I might write a guide on how to repair tracks on PCBs.

When repairing tracks on something like a gfx, hdd or a mobo, it isn't as simple as just soldering a jumper wire to bypass the break. Why?
Well it comes down to physics and the way electrons behave at high frequencies. When a computer or any high speed circuit is designed all track positions, spacing, thickness and length are factored in to suit the particular signal. The physical layout affects: resistance, capacitance, inductance and propagation speed of the electrons them selves. Change these properties and the signals: distort/delay/advance/ lost/cross talk etc...

Therefore it is crucial that when repairing tracks that we maintain it to spec as close as possible. Ok here is my technique.

Today I used this old 3GB quantum hdd and punch a track with a knife for this demo.


Ok thats is cut through. I start by using a jeweler's flat head screw driver and gently scrape the lacquer off a few mills down either side of the break until I see bare copper.



Next I get a good soldering iron, you can get Anti static ones or you can ground a normal one with a wire/aligator clip lead from the iron body to say? you computer case. This will ensure you dont kill what you are soldering. Also ASD mat or the bag the board came in to lay your work on.

Ok in the pic below you melt a blob of solder across the bare copper to tin it like so. then just lift it off after few sec. The blob will stay with the iron tip and leave it all tinned.


Now its all tinned. mmm looks nice



Now I get a wire and strip it until all the strands are out like this, then I tin one single strand. This will make it easy to solder it to the tracks.
Note!  that was one rough looking tinning on that wire, it was for the purpose of the pic as I was holding the cam in one hand so I did it again after.



Then I cut the length needed, that was too much for this job in the pic. I ended halving it. If the track you are fixing goes around a bend shape this tinny wire to match.



Now I placed the wire on top of the break and heated one end then the other. Now it is soldered on. But wait! this is the hard part. To make sure you solder it on proper and good, I run a clean blob of solder across the whole lot, this also makes it very clean, neat and a strong connection. Here is the finished job






Use a multi meter to test connectivity by testing at the end points of the track, ie. at IC pins or PCI slot or what ever they lead to.
You can finish off the whole lot by insulating with some kind of adhesive, I like to use silicon sealant. This will protect against shorts against other objects ( back plates,screws, case blah blah) and also prevent the bridge from being knocked of if you accidentally knock it on something.

There! I hope that helps some one for future reference.  I recommend doing this only if you can solder well if not get someone who can to help.
2010/02/17 15:20:29
stephen92

I'm a little lost on the transition between the 3rd and 4th picture. You have a glob of solder on the PCB, did you take it off after transferring some of it into the lane?

Other than that, awesome (and quick) guide. I've been teaching myself some stuff do do with a soldering iron, I can add this one to the list.  BR him
2010/02/17 15:27:18
Tweaked
If your warranty is still intact, do not attempt repair yourself.  Send product in to EVGA.

Very nice Vlad.  This should be very useful for those who are out of warranty or have voided their warranty.  Def BR worthy.  I'll leave it in General Discussion for a little while, but then I think I'll sticky it in the General Hardware section.  One thing, could you please add more pics to clear up some of the details mentioned by Drdoomuzi4u?
2010/02/17 15:28:36
vlad01
Yes i did. the blob doesn't stick to the tracks, it stays on the end of the iron. It only coats the tracks.
2010/02/17 18:53:16
LonelyStoner
Oh well. 

Luckily i didnt do any repairs on my own. I thought i would just use my $5 solder and $1 soldering iron and just patch it over the marks. That would get the job done. 

If my dad ought to do it? He'll just bring the welder's 'firegun with blue flame' and roast the board to a nice, soft and tender state. He'll go 'There, we are finished.' And he'll give me that cute smile.



2010/02/21 12:59:57
TheCrazyCanuck
Good guide, I would also add that flux can be your best friend when soldering fine points like these.  The solder you use on electronics comes with flux at the core (don't use acid core solder!!!) but you'll find that the melted solder will flow to the traces better if you apply some manually as well.  To remove the solder use a thick brush (like you would use for painting) and isopropyl alcohol.
2010/03/27 16:00:22
jcitron
This is an excellent guide, Vlad.

Way back in my younger days, about 30 years or so ago, I used to do this for a living. The only suggestion I'd make is to remove the extra flux and any solder beads that end up on the circuit board. The little beads can end  up falling down on some leads and shorting them out. Also the old flux will attract dirt, which can sometimes be conductive. To clean the flux, use alcohol, or if you can find it around anymore De-Sol which disolves the flux completely.

At this point in the game, the trackwork has gotten too small for my eyes even with a magnifyer. When etches break now, I throw the part away and buy another one. It's less frustrating that way.

John
2010/05/26 14:14:15
quadlatte
Remember also that this will only work on surface traces, if the pcb is cracked then and hidden trace can also be damaged as most pcb's now are multi layer.
2010/10/14 00:31:14
4thofjuly
Hmm... my quick fix used to be simply grab small aluminium foil make a tiny strip of it to match the track etc, and simply tape it to the board :). Or better super glue the ends if tape seemed to be not working great.
2010/11/05 06:48:51
simonetti
Well done! Nice job, and nice pics.
 
I am the kind guy who hates to throw away stuff without first giving it a shot of fixing it myself.
 
Thanks!

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