How do you repair damaged PCB pads/lands?

[Okto1984]

Although I was being careful, it wasn't careful enough. During component removal a couple of the smaller lands fell off the PCB

Is there some kind of safe, reliable repair I can do? I've found various repair kits for this problem - but they're amazingly expensive. I'm wondering what do other people do? Is it the end of my circuit board, or can it be saved? Any advice on tried methods would be greatly appreciated.

[Bazz4CQJ]

The loss of two small lands should be repairable without too much difficulty but it's hard to be specific without a picture. Silver-loaded paints and adhesives are available but tend to expensive. I've just used fine wires held in place with dabs of epoxy.

B

[Herald1360]

Bazz's technique can be used to practically recreate a PCB if necessary. If the tracks are really fine it may be easier to use 30AWG wirewrap insulated wire and connect between the damaged pad pin and the pin at the far end of the track.

A stick of hot melt glue can be used with your soldering iron for instant tacks of the wire to the PCB.

[julie_m]

I've had to do this a few times. It's annoying. Even with a temperature-controlled iron, the adhesives on some ancient PCB boards are vulnerable to melt; and the copper has a greater affinity for the solder on the tip of the iron than it has for the board. The surface tension in the pool of solder does the rest; ripping the copper land from the board until the trace breaks at the point where the heat has not reached and the adhesive is still holding.
Bmmer!

Use your favourite adhesive to hold the component in place on the board, in case the remaining soldered connections are insufficient to support it mechanically. Then solder short lengths of "bodge wire" (a.k.a. wire-wrap wire) between the component lead and the remains of the PCB trace. If you cut the wire to length, then very carefully pull the insulation a few millimetres away from the end of the wire and again cut off the bit of insulation which overhangs the end of the inner wire, you can then push it back towards the component; leaving the wire properly insulated and a neat, bare end to solder.

EDIT: Obviously for power, ground and speaker out lines, you probably want to use something like 18 SWG bare tinned copper wire, with sleeving over it.

[Peter.N.]

I always used a strand of wire from a multi strand lead in my TV servicing days.

Peter

[Leon Crampin]

A good way to make replacement tracks for printed circuit boards is to choose an appropriate gauge of tinned copper wire and hammer it flat into the appropriate width on a hard surface with a steel hammer. For a component pad, form a tight loop with the ends butted before hammering flat. Bend the wire to the curve of the required track before flattening.

With care and after a few trials with wire gauges, this technique can produce very reasonable tracks. Sticking them to the substrate can be tricky - I use superglue, but in minute quantities. If you get it onto an area you wish to solder, it works as a highly effective solder resist.

Leon.

I do the same as above but don't bother with the hammering flat bit. Hot melt glue can be soldered through i.e. stick your iron into it when it melts ordinary soldering can be done.

[threeseven]

Adhesive backed copper foil is available for the Terrarium market. It is used for joining glass panels with solder.
Personally though, I always just use a wire strand.

[Outrun_uk]

I tend to use the smallest gauge tinned copper wire/wire wrap possible and take it to the next solder pad in the circuit or scrape a bit of resist off the track, tin it and attach there. A lot depends on the board layout and available space.

Just a quick word of warning, don't use superglue to tack the repair down, I recently had a manufacturer-repaired piece of kit where they had done this, the fumes produced when heated with a soldering iron are most unpleasant and if gets into your eyes you will most certainly know about it *very* quickly... ask me how I know

[Okto1984]

Thank you each for the suggestions. I've gone with a thin wire from the nearest component to the missing component, as the remaining traces are very thin and solder just wouldn't take to them. It works great however and I'm not too worried about making it perfect inside, just safe and functional.

I'm surprised nobody is making an affordable repair kit though, I would certainly try one if it existed.

[G6Tanuki]

One trick I've used where the pads for flying-leads to attach to a PCB have lifted is to fit 'turret tags' [ e.g RS part no. 433-573 ] to the holes originally used for the flying leads.

Do whatever you need with wire etc to connect the underside of the turret-tag to the remaining trace, and then solder the flying-lead to the notch in the end of the turret-tag. Apply some suitable glue [I use a two-part epoxy] over the damaged track-area to contain the repair and help retain the turret-tag from below.

This is a great way to deal with leads between a PCB and power-transistors mounted on a heatsink, or links to big clamp-mounted electrolytic power-supply capacitors.

[McMurdo]

Originally Posted by Outrun_uk

don't use superglue to tack the repair down

Worth mentioning that most commercial pcb track repair kits use superglue gel and an activator

[m0cemdave]

Originally Posted by Outrun_uk

Just a quick word of warning, don't use superglue to tack the repair down

Haha, yes, instant tear-gas.

I discovered that the hard way too.

[Nickthedentist]

Originally Posted by Okto1984

... the remaining traces are very thin and solder just wouldn't take to them.

I find if I scrape off the green solder-resist with a tiny screwdriver, polish the copper track with a fibreglass pencil, tin the track with multicore solder, clean off the excess solder with desoldering braid, then carefully bend a strand of freshly-tinned copper wire so that it runs precisely along the length of the track (to the nearest land either side of the break), and finally solder the wire to the track using fresh solder (and the tiny screwdriver to keep it pressed firmly down until the solder's set), I get a very neat repair indeed.

You need practice, and proper tin/lead solder of course.

N.

[Diabolical Artificer]

I've had this problem whilst replacing a SMD op amp on a modern mixer. The tiny closely spaced pads on one side of the op amp lifted. It was a nightmare to reconnect the op amp pins to the PCB tracks.

I used fine wire as most have suggested, but the result wasn't neat. One other problem I found when working on this board was accidentely losing an SMD capacitor which stuck to the iron and in a moment was lost, never to be found.

I have in the past when working on through hole PCB's, replaced tracks with carefully lifted tracks off scrap PCB's. I stuck them in place using Araldite with a 3:1 mix of glue and hardener, then carefully soldered it to the damaged track. It is a very fiddly job.

Andy.

[MotorBikeLes]

My Ex used to make jewelry, and used both silver and silver plated copper wire in many thicknesses for making "corn dollies". I found this really good for pcb repair, as it took solder so much better than ordinary copper wire, tinned or otherwise. She presented me with a few coils of different thickness which I can still use.
I have repaired holes in line stages of Thyristor LOP colour TVs, recreating the board with epoxy after soldering up the various components. (A bit of adhesive PVC tape on the back whilst the epoxy sets.) I have fine nosed pliers, fine wire cutters and fine round nosed pliers which she used to stock, and these permit the shaping of the wire with "component holes" and then to follow a track layout. Not often needed these days, but always to hand.
Les.