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12/27/2017 7:41:18 PM
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Hot Plug
Years ago, when I worked for GE Computer Division, we investigated  the requirement to have a hot plug capacity. This allowed insertion/removal of system boards while the power was on. 

We found, after some in house tests, that our existing board connectors pitted when inserted/removed with power on - no surprise actually. But, what was more problematical was that after a relatively small number of cycles, the connection failed completely. After feedback with our connector vendor and some design changes, the problem was remedied.

Many years later, in a situation where the hot plug functionality was again required on a system under design (different company), this historical fact was replayed in a meeting involving various contributors. The system design manager "looked" into it by asking the connector vendor what they thought about the issue. They replied that they had never heard anything like that before. Our system design manager decided that it was not an issue, and proceeded to utilize the existing connector without futher investigation. He just didn't want to deal with it.

Who knows whether the issue became a reliability problem or not. Chances are, that it was OK, or at least would never have been discovered. But, it does go to reinforce the unpleasant truth that way too often, potential design issues are skipped over, rather than actually delt with.

12/23/2017 3:18:34 PM
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Number of connections

Thanks for the pointer to the connector review. One of the best kept secrets in the connector world is the number of make and break cycles that can be made before the connection starts to degrade. The article keeps the secret. Even when I worked for a connector company it was impossible to get official confirmation of rumoured numbers. I might add that those rumours a probably far less than one imagines.

I have written two blogs on connectorswhich I hope are of interest

"Which PCB Connectors Are Best?" 

(h t t p s ://w w w

and "Unusual connectors"

(h t t p s ://w w w

remove the spaces to get to the URLs


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