What is considered a "professional" PCB trace repair?

[Shadrock2]

Although it doesn't happen as much to me anymore, I always dread overheating a solder pad on a PCB.
How would you re-attach to the PCB? I have used a dab of hot glue before.

Worse... you get a broken trace or a resistor runs hot over time and the surface of the PCB underneath the traces has turned brown and is weak.

I have used small pieces of wire that I soldered to the trace to bridge the gap. Sometimes I have run an insulated jumper wire all the way to the next component in the circuit.

What would be considered a professional quality repair in these cases?

[J M Fahey]

If the trace or pad is relatively wide I reglue it with a small dab of epoxy , it gets instantly cured with solder heat.
No mystery, it's what it was glued with before

[drewl]

Depending on the damage, sometimes it's better to remove the damaged area, remove the insulation from the trace further down and solder there or use the proper wire to repair a trace.

We also have the green coating for repairing the boards.

[Tone Meister]

Can some of you professional techs/engineers post some pictures outlining the procedure and materials used where you've repaired damaged PCBs? This is a question I've wanted to ask and didn't.

[Randall]

I keep a little box of the leads clipped from new components, and carefully solder them in place of a damaged trace.

[gui_tarzan]

Same here.

[olddawg]

A properly repaired board will outlast the unit. In the case of cracks, drill a hole at each end of the crack to stop the spread. If a corner of a board, or a board is cracked in half, braid soldered to large areas will hold it together and of course 5 minute epoxy is your friends. Many boards are made of resin impregnated paper and will carbonize when burned. Those areas a conductive. So a Dremel tool to grind out the bad area works well. Then you jumper the interrupted traces. It's a good idea to keep some old boards around. You have no idea how many times I have cut a blank area from a junk board to use with a little epoxy to repair a damaged board. In some cases, a dab of hot glue or silicone will stabilize jumpers so they will not move over time. I find it better to jumper from a component to another component in most cases rather than scraping, fluxing, and jumpering a trace. Use the appropriate wire and do a clean job.

[mikeydee77]

When I used to work in a professional environment (high frequency telco switching stuff) mods and rework would be extremely neatly using kynar wire-wrap wire and secured to the board with Tak Pak and activator. Some mods looked so neat with multiple wires running up and down large boards in parallel maybe half a dozen wires wide. 382/7455 - LOCTITE - ADHESIVE 382 & 7455 TAK PAK KIT | Farnell UK

Having said that I tend to follow the Randall school of thought and also like to use glue to secure components to top-side of the board if they are likely to be top heavy or subject to vibration or movement.

[52 Bill]

Every problem is different so every solution is different. I think we've all just bent a lead over and soldered it down to a trace when the pad has been damaged. And some of us have used the self-adhesive copper foil tape to replace pulled up traces. And some of us have patched in a new section of matching board in cases where the board has been so carbonized and burned that the only way to save it was by drastically grinding out the bad section.

In any case, what olddawg said is the real pro factor here, "do a clean job".

[g1]

If you want to get real fussy, google pcb repair kit

[bsco]

Pace makes a bunch of track and pad repair kits.. .I have used these before....and eyelets and funnelets....for thru-hole repair

[tedmich]

a little epoxy won't help some..

make a new one!

[J M Fahey]

Well, I HAVE made new ones in desperate cases.

1) I attach a piece of drafting paper (a.k.a. Vellum) over the PCB

2) I trace it with an Engineer/Architect drafting pen, 1mm tip loaded with China ink (being European based we call it a Rotring or Staedtler pen and use Pelikan ink)

3) in a simple PCB, I use that drafting to hand draw a new one with a Sharpie indelible ink pen; in a complex one, I scan it and then edit it in Corel Draw or similar, then laser print it on Photo/coated paper and thermal transfer it to bare copper.

[nevetslab]

On the extreme side, I had to restore a Fender TB-1200 Bass Amp, that suffered major power supply foil damage on the bottom side of the PCB. In this case, I cut off the burnt traces, at the two ends of the high current trace, scraped away the solder mask, then laid in adhesive-backed 3M 0.003" thick x 0.50" wide copper foil, routed the replacement foil, then laid in lead-wire 'bridges to restore the circuit. And, after finishing with that, covered the new area with kapton film.



In another area of the same amp, having lost a skinny trace that delaminated from the board before burning open, I identified the two ends, chopped off the burnt trace on the top side, and on the bottom, laid in 26AWG solid/Teflon sleeve to restore the circuit, forming small hooks to wrap around the component leads, and added a little dab of RTV after I was thru (not shown in the photos here)



In general, if there's still quality foil present around a failed trace or solder pad, I'll scrap away solder mask up-stream from the damage (say, lifted pad), tin the trace at that area...say 1/2" worth of trace. then prepare 26AWG solid buss wire (removed the Teflon sleeving of the same wire used above), form a hook to wrap around the component lead on that lifted pad, put the hook into place, close the loop of the hook and tack-solder it closed/hold it down against the PCB. Then, flow solder on the tinned lead at the other end, having first routed the wire to follow the trace.

I also make liberal used of 'spent' solder wick on heavier traces that have failed, such as on PCB-mounted input or output jacks where prior techs did a botch job. Lots of methods work.

[R.G.]

There's a difference between repairing broken/lifted traces and repairing burned PCB base stock. In tedmich's very telling photo, you see a bit of PCB underlying stock that has been burned and carbonized. If there is sufficient voltage/current available, those burned areas are what we used to call "PCB Cancer". The carbonized areas conduct, and if there is enough power available, they will heat up and continue burning through the base stock. It is particularly dangerous if the board/traces carry AC mains power, as there is a near-infinite source of power for continuing to eat the PCB stock.

I designed and worked on power supplies with logic voltages in the multi-hundred ampere range and also on AC mains PCBs, and this was something we all had to be aware of.

To repair a board that's this damaged, you have to either cut the damaged section away and replace it somehow, or as tedmich said, replace the whole board somehow.