PCB that is physically broken (corner knocked off) - repair with suitable glue? - Page 1
Forum section: electronics / repair

author: SolderSucker
author_rank: Regular Contributor
timestamp: September 26, 2019, 12:22:39 pm
content: I have an old, large arcade game PCB where the corner has been physically broken off. About two dozen tracks are affected and one chip.What is the best way to repair such a break - glue it (what type of glue to use though?) and re-make the tracks with fine wirewrap wire? As the affected chip is a RAM I may in fact be able to leave the corner off, tidy up the track, piggy-back the RAM onto an adjacent RAM (all part of the same area of the circuit) and re-route the select line and the data lines (the address lines are of course shared) but in some ways I'd like to repair the actual PCB break if it's possible. The affected part is of course triangular and about 2 by 1 inches.There's of course not going to be much strength there if I do glue it.What do you all think?

author: pbarton
author_rank: Frequent Contributor
timestamp: September 26, 2019, 01:32:52 pm
content: I don't think that a glue has been invented that could repair a PCB corner, butt jointed together, unsupported.I reckon that the broken corner requires some form of support, something like an 'L' shaped corner from a "Picture Framing frame Molding".The PCB fits into the molding glass slot.Kynar wire to repair PCB track.

author: SolderSucker
author_rank: Regular Contributor
timestamp: September 26, 2019, 01:56:04 pm
content: That's a good idea about something like picture frame molding, thanks.

author: mikerj
author_rank: Super Contributor
timestamp: September 26, 2019, 02:00:38 pm
content: Hopefully this is only a double sided PCB? If there are inner layers it's going to make things tricky.

author: SolderSucker
author_rank: Regular Contributor
timestamp: September 26, 2019, 02:09:55 pm
content: Thankfully yes, it's a double sided board.

author: Gyro
author_rank: Super Contributor
timestamp: September 26, 2019, 05:51:59 pm
content: Quote from: SolderSucker on September 26, 2019, 12:22:39 pmKeep a bit of slack in the bridges, you don't want to tear tracks off with any post-repair flexing or movement.

author: TERRA Operative
author_rank: Super Contributor
timestamp: September 27, 2019, 12:29:29 pm
content: Is it a clean break, or is the break diagonally through the thickness of the PCB? If it's diagonal, you'll have more luck glueing it with the increased surface area.I'd try a good superglue (my go-to is Loctite 401) rather than watered down dollar store stuff.Then repair each trace with magnet wire/wirewrap wire/kynar, etc.Can you post a pic so we can see the break to make a more accurate assessment?

author: SolderSucker
author_rank: Regular Contributor
timestamp: September 27, 2019, 01:56:12 pm
content: It's a 'rough' break.Can't take a picture right now but will try to do so. Thanks for the help.

author: Cyberdragon
author_rank: Super Contributor
timestamp: September 28, 2019, 10:25:31 pm
content: I've had success with multiple coats of superglue on the edge and top of a smashed board and bridging the tracks with excessive solder. This was even in a corner where a daughterboard plugs in (the break was caused by a falling object when the other board was unplugged). However, this was a 60s single sided board and probably a different material than yours.

author: james_s
author_rank: Super Contributor
timestamp: September 28, 2019, 10:38:19 pm
content: Epoxy or superglue, clamp it tightly and when cured bridge the traces with thin bare wire. It won't be as strong as new but it should be strong enough to do the job.

author: vk6zgo
author_rank: Super Contributor
timestamp: September 29, 2019, 01:19:38 am
content: Two part epoxy, such as Araldite or equivalent.Surfaces must be scrupulously clean, & supported for at least 12 hours after application.If it doesn't get in the way of the conductors, a piece of unclad PCB material glued across the join will ensure rigidity.

author: SolderSucker
author_rank: Regular Contributor
timestamp: September 29, 2019, 01:04:26 pm
content: Thanks for all of the great suggestions.