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layer 2 groundplane disconnects after hand solder

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#58568

layer 2 groundplane disconnects after hand solder | 10 April, 2009

Layer 2 is the ground plane layer of a 4 layer board. After installing a 2.5 mm DC power jack and 0.1 center SIP header by hand, the ground pin disconnects and causes an open.

My board supplier said they passed Electrical Test. Prepreg was within date and desmear was done properly.

Anybody see this before? Any explanations are appreciated.

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#58569

layer 2 groundplane disconnects after hand solder | 10 April, 2009

Hi Jeff,

Your board supplier could be correct in this way.

The board could have had just a hair left of copper on the circuit, which would hold up under the electrical test process, but once you powered it up, then there was enough juice to burn the copper hair away, which now is causing an open.

it sounds far fetched, but I ran an electrical test dept. for 10 years and have seen this happen many times.

This does not take responsibility away from your board supplier. They are still responsible for the error, unless they can prove that you over powered the board.

They should be at least covering the cost of the Bare PCB.

Best Regards, BoardHouse

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#58577

layer 2 groundplane disconnects after hand solder | 13 April, 2009

BoardHouse, Thanks for the reply. The board supplier did cover the cost of the bare boards.

Five years ago I saw a different part pass ET only to fail at final assembly test as well. One engineer called it "acid trap" on the inner layers where the trace etched down to a very small neck when it reached the pad. A little current run through the trace would blow the neck of the connection. I still do not know what caused this to happen and why layer 3 was OK.

One possibility is layer two was severely over etched. Maybe they pulled 1/2 oz copper instead of 1 oz copper and ran it through the etcher too slow.

Best regards, Jeff

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