Gold Edge Connector

Hi lads long time no post...

I have an issue with a PCB, its a PCI card that we manufacture for a customer of ours. The customer is seeing a problem with contact on a PCI card with the motherboard, the PCI card is removed from the board wiped and the card works again.

Speaking as a computer user, this background info is not right, I fit PCI cards regularly and this is very unusual process and doesn�t seem logical.

My first impressions were that the quality of the raw PCB may be inadequate. I sought the advise of a local PCB fab who measured a sample of PCB's at the connector and found that the cards were within the spec of the fab house in China and within their manufacturing guidelines for their plant!!! i.e. the gold and nickel thicknesses were ok, Gold plating with a thickness of 0.75 Um (30u�) over a nickel plating of 2.5Um (100u�), the gold was electroplated and HARD.

An exercise was undertaken to determine 'contamination' on some sample card that were sent back to us from our customer, know fail field fails, they were tested by a university and EDAX measurements were taken of chemical compositions found on the edge connector, SEM images were also supplied but to my knowledge nothing striking was found. Other than CARBON on the gold surfaces.... Could be anything, but this eedge connector having two surfaces for contact it would seem unusual that only 1 side having contamination problems would lead to an �open circuit� and the card not working.

I ask the question of card aging, would a card in the field last 1, 2 -10 years without seeing degradation to the gold edge connector. Would humidity play a fact on the �rapid� aging process. If the pc units were stored in damp conditions say a basement could the gold edge connector deteriate etc etc.

Any ideas... my work continues�

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