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A while back I designed a fairly expensive 3-layer PCB (gold plated RF laminate, not cheap).
Unfortunately, we have now discovered that I've accidentally put a stiching via, i.e. a vias for connecting top and internal ground planes in the centre of an important RF line which is now permanently shorted. There are 5 PCBs that we would ideally like to repair.
The via diameter is small (0.127mm) and in the centre of of 0.65mm line meaning removing it using a drill will be challenging..
However, I spoke to one of our engineers and he mentioned that he had heard of people "burning away" vias by simply passing a high current through them. The ampacity of this vias should only be ~1A so the amount of current needed might not be very large (a few A at a ~5V or so)
I was wondering if someone has actually tried this? My worry is that the pcb will simply de-laminate as it heats up.
The alternative would be to find a specialist company that can use laser ablation to remove the via, this might still be cheaper and faster than new ordering a new PCB
Unfortunately, we have now discovered that I've accidentally put a stiching via, i.e. a vias for connecting top and internal ground planes in the centre of an important RF line which is now permanently shorted. There are 5 PCBs that we would ideally like to repair.
The via diameter is small (0.127mm) and in the centre of of 0.65mm line meaning removing it using a drill will be challenging..
However, I spoke to one of our engineers and he mentioned that he had heard of people "burning away" vias by simply passing a high current through them. The ampacity of this vias should only be ~1A so the amount of current needed might not be very large (a few A at a ~5V or so)
I was wondering if someone has actually tried this? My worry is that the pcb will simply de-laminate as it heats up.
The alternative would be to find a specialist company that can use laser ablation to remove the via, this might still be cheaper and faster than new ordering a new PCB