#19 Circuit board trace repair

[Radio Tech]

#19 Circuit board trace repair




In this video we look at repairing circuit boards that has had the traces lifted and broken off the board. Then we show how to repair a trace that has been blown due to a short circuit. I lost the final step showing prep to install the capacitor to the new pads due to equipment failure.
Perhaps one day I can obtain the proper video equipment to aid in recording of smd rework.









Epoxy  https://www.all-spec.com/products/CW2500.html
Tape  https://www.all-spec.com/products/1656-05.html
Copper  http://www.ebay.com/itm/272047983112?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT




TRXbench  https://www.youtube.com/channel/UClqWe58x9q6jx61gB16731A

[Radio Tech]

I would also like to hear how others repair circuit board damage.
So feel free to throw out some thoughts tips and even failures.

[Shock]

I would also like to hear how others repair circuit board damage.
So feel free to throw out some thoughts tips and even failures.

There are a couple of catches for new players with shorts, not repairing the short properly first (losing all your good work) and removing carbon from the pcb or insulating against it.

For shorted traces/tracks I have mostly used Kynar wrap wire and enameled wire in the past, obviously it doesn't look as good or work in situations where it affects the circuit, all depends if it's going to be a keeper.

There is a couple of pace video series on youtube ones called "adventures in repairs" that shows doing beveled cuts, quite interesting.

When doing those smd capacitor pads you might be able to save a bit of time by laying one piece down covering both pads, and after the epoxy has set trim and remove the middle. I've not tried it but thinly tinning the copper replacement before shaping it may make it easier as well.

I've got a power supply repair at the moment and it appears the PCB is conductive, that ones going to be interesting.

[Radio Tech]

I know what you mean about carbon track on the pcb. Worked on an amplifier last year that had 1800 volts on the plate of the tube. power supply board blown and left some carbon on the supply board. I used a wire wheel and a dremel to remove the carbon, and covered the area in epoxy. 15 seconds after power up is again started to arc and burnt a hole in the board before I could shut down.

Sounds interesting about the Kynar wrap wire and the videos. Will look that up and see what I fins. Thanks.

Never thought of laying the foil down then trimming it out.  Most of the time there are many tracks next to the area where the pads are missing.  May try that on a test board and see how it goes. Not going to rule that one out.

A conductive pcb? Oh my that is going to be an interesting one. Good luck on that. Had a board one time covered in that yellow epoxy that had become conductive. That really caused issues. But the board itself will be a night mare. Once had a control board that fed a PLC that transformer leaked on. It became conductive, that was a tough one to troubleshoot.

Thanks for the reply. 

[Shock]

A conductive pcb? Oh my that is going to be an interesting one. Good luck on that.

Yeah not really sure what is going on I need to stick my nose back in it and order parts, was getting arching across the PCB while I was taking measurements, only ~30VAC (I hope) but you don't want to hear that noise on the other side of a transformer . I thought I caught it with my eye around the smoothing caps so perhaps the caps caused it.

The PCB looks contaminated which sort of lead me to that conclusion.

[Radio Tech]

A conductive pcb? Oh my that is going to be an interesting one. Good luck on that.

Yeah not really sure what is going on I need to stick my nose back in it and order parts, was getting arching across the PCB while I was taking measurements, only ~30VAC (I hope) but you don't want to hear that noise on the other side of a transformer . I thought I caught it with my eye around the smoothing caps so perhaps the caps caused it.

The PCB looks contaminated which sort of lead me to that conclusion.

Keep us informed on what you find. Sounds very nasty. Hope it does not turn out to be non repairable.
Going to be busy here at work for the next few days, so many things to do in the home shop. Cannot wait for my 13 days off.