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Need help spotting a PCB short
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thinkfat:
Hi,

I've recently received some PCBs from manufacturing and they're all faulty, they have a solid short between the ground plane on the first inner layer and the 3.3V power plane on the second inner layer. The PCBs were made with KiCad and they pass DRC. I've attached the Gerber files and also the KiCad PCB file here, I'd be glad if you could help me find the problem with my design. The minimum track/clearance should be 6/6 mil. The PCBs were made by Aisler, I have used them before and I was always happy with the results.

The KiCad PCB file has been renamed as .txt due to restrictions with file types, you can just rename it back to .kicad_pcb.

Thanks,
Matthias
 
langwadt:

--- Quote from: thinkfat on May 04, 2019, 07:50:08 pm ---Hi,

I've recently received some PCBs from manufacturing and they're all faulty, they have a solid short between the ground plane on the first inner layer and the 3.3V power plane on the second inner layer. The PCBs were made with KiCad and they pass DRC. I've attached the Gerber files and also the KiCad PCB file here, I'd be glad if you could help me find the problem with my design. The minimum track/clearance should be 6/6 mil. The PCBs were made by Aisler, I have used them before and I was always happy with the results.

The KiCad PCB file has been renamed as .txt due to restrictions with file types, you can just rename it back to .kicad_pcb.

Thanks,
Matthias

--- End quote ---

attach a big powersupply and see where it gets hot

thinkfat:

--- Quote from: langwadt on May 04, 2019, 08:26:11 pm ---attach a big powersupply and see where it gets hot

--- End quote ---

Tried, 12V@5A, can't make it budge. The only place that gets warm is the immediate vicinity of the pads where I inject the power. I tried multiple locations. I don't have a thermal cam or freeze spray, so I'm spraying the board with IPA.
thinkfat:
Bah, nevermind. I found it. You won't be able to see it in the files I uploaded. I re-downloaded the PCB file directly from Aisler and it seems I had forgotten to re-fill the polygons after a rushed last-minute change. There's two GND vias that connect the 3.3V plane and the GND plane :-(

I feel stupid. Proof of my failure attached.
jbb:
I know the feeling. Can you drill out the offending holes to break the shorts?

It turns out that the PCB house will generate their flying probe e-test from your Gerbers, so a flaw in your Gerbers will be faithfully built and sent to you :-(
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