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Chat => Chit Chat => Topic started by: Weaver on February 11, 2020, 03:08:31 AM

Title: USB charging sad
Post by: Weaver on February 11, 2020, 03:08:31 AM
I have a mains distribution block which very conveniently has a number of USB sockets in it. Recently I managed to pour coffee all over it and some I suspect went down the USB sockets themselves. Sometime passed and one night I had a nightmare experience where my the battery percentage showing on my iPad was slowly creeping down. A load of fault finding and in the end the only thing we could find which worked properly was a white Apple USB mains charger plug which was plugged into this distribution block, while plugging USB cables in directly didn’t work. Then we remembered it was perhaps something to do with coffee.

Since it has not been blown up and it does deliver some power out of the USB sockets, just not enough it seems, what can we conclude? Could it be simply that the contacts are covered in coffee giving higher contact resistance and so lower current? If so can we perhaps fix it by just scratching or cleaning them ? It may not be possible to get at the surfaces though. It’s not worth expending a huge lot of effort as it only cost around £15.
Title: Re: USB charging sad
Post by: roseway on February 11, 2020, 06:53:51 AM
I think you've answered your own question. That distribution block will always be suspect after spilling coffee on it, however much you try to repair it. Just get a new one.
Title: Re: USB charging sad
Post by: Weaver on February 11, 2020, 12:40:38 PM
Thanks Roseway. I had thought of at least trying to plug and unplug the usb a few times to see if that would be enough to scrape any crud off the surfaces though.

I wanted to ask is my logic correct? I don’t understand the details of the iOS/iPadOS UI here - Is it possible to have a situation where the device will deliver some current, enough such that the dc will be detected as ‘present’, but there is actually no current worth anything, or at any rate some amount that is not enough to charge the battery? The green battery symbol and lightning zigzag symbols appear at the top rhs in the iPad (For those familiar with iPadOS) whatever that may mean.
Title: Re: USB charging sad
Post by: Alex Atkin UK on February 11, 2020, 03:01:26 PM
I'd suspect its corroded the PCB itself, I honestly wouldn't even try to use it as depending on where its damaged you could just as easily end up with too much voltage/current as too little, if the voltage sensing circuit has been compromised.
Title: Re: USB charging sad
Post by: burakkucat on February 11, 2020, 06:27:00 PM
I don’t understand the details of the iOS/iPadOS UI here - Is it possible to have a situation where the device will deliver some current, enough such that the dc will be detected as ‘present’, but there is actually no current worth anything, or at any rate some amount that is not enough to charge the battery?

I believe quite a lot of Apple devices are "sensitive" to out of specification power sources.  :-\
Title: Re: USB charging sad
Post by: Weaver on February 12, 2020, 10:29:21 AM
@Burrakucat That’s the general impression I have picked up in my readings.

@Alex Right, in the bin it goes.