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Sparks from USB ports!

D

diegobgr

macrumors 6502
Original poster
Nov 22, 2009
340
0
Hello.

I have noticed that my iMac makes sparks when I try to connect something to the USB.

I think that there are only make when it's something with external power, like a printer or a external hard disk. With a pen-drive or the iPhone, it doesn't happen.

What can you tell me about this?
 
That really isn't normal. Is your desk made of metal cause that can cause a weird transfer of current between devices. There shouldn't be sparks out of a USB as its only putting out 5V which is nowhere near enough to make a spark.
 
diegobgr said:
Hello.

I have noticed that my iMac makes sparks when I try to connect something to the USB.

I think that there are only make when it's something with external power, like a printer or a external hard disk. With a pen-drive or the iPhone, it doesn't happen.

What can you tell me about this?
Click to expand...

Holy *****
 
Dude, just so you know, there are enough amps in a USB port to kill you. Seriously!!!! Don't touch that computer until you take it in to get it fixed.
 
It's pretty normal, I assume the sparks you mean aren't as big as what people seem to be assuming from your statement?
 
diegobgr said:
Hello.

I have noticed that my iMac makes sparks when I try to connect something to the USB.

I think that there are only make when it's something with external power, like a printer or a external hard disk. With a pen-drive or the iPhone, it doesn't happen.

What can you tell me about this?
Click to expand...

What iMac do you have? My 2010 27" iMac does this when i plug in an externally powered device (printer, hard drive dock, etc.) I have also been wondering if this is normal.
Thanks.
 
So, it's normal?

People taht say that it doesn't happen, could tru it? It doens't happen always.
 
I used to get this on a G5 with firewire devices pretty regularly. Just little tiny sparks that jump between the cable and the area around the port on the tower. Freaked me out at the time
 
Sparks from Macbook usb ports

I'm having my brand new Macbook pro tested at an Apple shop right now for this problem. In my case, as well as the sparks, the remote monitor (running from the mini display port) gets shutoff, then fills with static.

Apple support say they've never heard of this problem so I pointed them to this forum. However, they say it should not happen, so that's why it's being investigated. Don't think this is normal, as some people are posting. It may not damage you but it may well damage your computer.

It seems to happen with USB hubs. I've tried it with two different brands and two different cables and it occurs in both cases. I can't get the problem to occur on my son's identical Macbook.

So if it happens take it up with Apple. Will let you know the next episode.
 
wombatwod said:
It may not damage you but it may well damage your computer.
Click to expand...

Well, given that 400mA near the heart can cause fibrillation and possible death... and that the USB specification states power draw at 500mA... it can do more than damage you if the hardware problem is serious.

Of course, I could be lying (or mistaken, or over-exaggerating) and want to scare everyone :p
 
This happens more frequently then most people realize.

Unfortunately taking it to an apple store will do nothing because I bet they will not be able to reproduce it.

It can be two things. ****** power in the building you are in, or lots of static. I'm guessing ****** power since you said it only happens with devices that are powered.

If you plug them into a UPS (a good one, not just a power strip) this should eliminate the problem.

This happened with most computers at my old work place and the only ones it didn't happen to (at least that I noticed) was the ones hooked to a UPS.

Oh and you can get shocked, just slightly though. I got shocked on both USB and monitor (vga) cables at my old workplace.
 
This happens to me every time I touch the metal casing around the USB ports by accident with the USB device I am plugging in. Both my old i5 and every MBP I've owned.
 
The most likely cause is that there is some problem with externally powered equipment using an electrical ground that's different from the ground in use on the iMac. This could be the result of improperly grounded hardware, bad grounds, different grounds (of which one is bad), or bad external wiring.

An experienced electrician can do a grounds and power test in under a minute for any mains socket. (You can too, with the right equipment.)

Idea: Get a good brand-name power strip and plug ALL the equipment AND the iMac into that same strip. This test will eliminate many possible problem sources.
 
Slightly off topic but my ATV sparks like a frickin maniac when you try and plug in the power cord. I mean a real bright white flash and a loud pop. :cool:
 
It's interesting that you say it only happens for powered devices - seems like there might be some kind of grounding issue. Is the imac plugged into the same distribution board as the external hard drive/whatever? Maybe try switching plugs to different sockets - one of them might have a dodgy ground connection
 
This happens to all my powered USB's when plugging them in, I think nothing of it, it always happened on my old computer too
 
Sparks from Macbook usb ports

Follow up to my earlier post.

The problem has been seen and accepted by Apple and I am getting a replacement Macbook. I'm afraid most of what's said in these posts is not correct. It would seem to be a genuine problem with the computer (Apple told me they don't use the word 'problem', or 'fault', they say 'issue'). More spin for you. Anyway, the clue that it is a real problem is that when I plugged the USB devices in, or just got the spark when I brought the USB near the aluminium case, my remote monitor on the mini display port went out. When the technicians saw that happen Apple got more interested. It happens whether the USB device is powered or not, and whether the Macbook is powered or not.

It can't be the 'capacitor effect' as it's only the USB case touching the Macbook case, not the actual pins themselves.

What level of sparking to a metal case is acceptable? None obviously.
By the way, a Macbook on battery is not earthed (grounded). What is the highest voltage inside it? Are metal cases a good idea? Hmmm?

Tomorrow I have to sign 'legal stuff' from Apple. Wonder what that will be.
 
More sparks from Macbook USB ports

Apple repair shop rang to say that the replacement Macbook,just received from Apple, has the same problem. What next! Could this be a design fault (sorry Apple - a design 'issue')?
 
My iMac sparks a bit when I plug in a mini display port adpater to a vga monitor. It only does it if the tip of the adapter touches the metal case around the port when I fumble to plug it in. I have not been too concerned about it because it doesn't always do it.

I do live in a pretty old apartment right now where the power may not be grounded so that could be the problem.
 
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