Has a PCB Been Powered?

[pyrotechsg]

I'm curious how a company determines if a PCB has been connected (powered-up) without powering the PCB during testing?

 

[Martaine2005]

That's a very confusing question. They cannot tell if a PCB has been powered up.
Unless of course it's a warranty return with burnt components on the PCB suggesting it was incorrectly connected up.
I'm sure there are microcontrollers that hold data on power cycles too, but they'd have to power it to read it.

Martin

 

[crutschow]

I'm curious how a company determines if a PCB has been connected (powered-up) without powering the PCB during testing?

Why do you think they want to determine if it has been powered up?
Certainly it will have been powered up during manufacturing test.

 

[pyrotechsg]

That's a very confusing question. They cannot tell if a PCB has been powered up.
Unless of course it's a warranty return with burnt components on the PCB suggesting it was incorrectly connected up.
I'm sure there are microcontrollers that hold data on power cycles too, but they'd have to power it to read it.

Martin

That was my thought, that to check it they would have to power it up and then of course it would have been powered. I was looking for a board for a refrigerator and the site said they would not accept returns if the board had been installed and it got me thinking, how exactly would they determine that. I guess microcontrollers that monitor power cycles could be used but that begs another question, how do they know how many times a board was powered during the initial testing?

 

[AnalogKid]

If the board does not have any form of non-volatile memory (flash, eeprom, latching relay, whatever), then there is no historical information. Of course, anything with a microcontroller on it can count, time-stamp, and remember just about anything.

ak

 

[Martaine2005]

For your fridge example, I'd guess it has connectors where a push fit would mark the pins or terminals suggesting it's been connected. Or simply placed in a sealed bag. Therefore not new any more, so no returns. That by itself begs another question, warranty of new board.
Perhaps under warranty, you can return it. If you connect it and your fridge still doesn't work, you can't return it for a refund.
That policy would 'rightly' discourage average Joe from ordering every new board until his fridge or washing machine fires up, then wants a refund for all the boards that didn't fix it.

Martin

 

[ivak245]

Most (if not all) control boards are sold with a strict "no returns" policy, although I have returned dead new boards to suppliers who knew me and sold me hundreds of good boards and other appliance spares. The supplier has no way of knowing if boards have been installed correctly, and have cooked something on power-up. If you have only ever bought 1 board from them, then your chances of a refund on a dead board are virtually zero.