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dodo_nutter · Jun 24, 2004, 06:18 PM

I've noticed that when my powerbook (1.5GHz 15") is plugged in it sort of vibrates sometimes when you lightly drag your finger tip across the palm rest or any large expanse of Aluminum. I thought this was just my fingerprint groves vibrating over the surface but i noticed it only happens when its plugged in to the mains.

Now i didn't think much of this until the other day when i had my PB on my lap, on charge, and my finger was doing the weird humming thing again which i find rather cool...anyway i was sitting surfing and my girlfriend leans over and stroked the back of my ear and her finger vibrated too!! Exactly the same way as it does on the surface of the PB!!

So i started experimenting. It only happened (her finger vibrating on my ear) if the PB was plugged in and i was touching it. If I was touching it and it was on battery...nothing...if it was not on my lap or being touched...nothing...but if it was on power and i was touching it, it happened every time!

Isn't this a little bit weird??!! I keep thinking electricity but how!?!?!

Any ideas!??

vinster · Jun 24, 2004, 06:37 PM

Originally posted by dodo_nutter:
I've noticed that when my powerbook (1.5GHz 15") is plugged in it sort of vibrates sometimes when you lightly drag your finger tip across the palm rest or any large expanse of Aluminum. I thought this was just my fingerprint groves vibrating over the surface but i noticed it only happens when its plugged in to the mains.

Isn't this a little bit weird??!! I keep thinking electricity but how!?!?!

Any ideas!??

It seems like some kind of low-voltage current. I read of others who have gotten mild shocks from their powerbooks when they're connected to a unearthed (ungrounded) mains socket. I have a rev b 15" aluminum powerbook and do not have this problem.

Have you tried plugging your computer in to various sockets around the house and see if there are any that don't give you the buzzing? Are you also plugged into a surge protector? If not, you might want to think about getting one.

dodo_nutter · Jun 24, 2004, 06:43 PM

Haven't tried the different sockets approach...ill try that one. Saying that its plugged in now and its not happening but it is on a metal paper tray.

Only grounding is through the third pin on the plug but i've got a surge protector lying around somewhere in the garage so i may go dig that out.

Its just a little disturbing knowing that im conducting something but not sure why or how seeing as it really shouldn't happen at all!!

Thanks for the info

rag on a muffin · Jun 24, 2004, 08:01 PM

i couldnt touch the screws on my ibook, it would shock me really bad, even when not plugged in. id say you are experiencing a low voltage AC shock, because i think your muscles are reacting to the electricity coming from your powerbook. the reason i think its AC, which stands for alternating current, is because your muscles contract and expand when electricity is put up to them. your body uses DC or direct current, which makes your muscle flex. when an AC current is put to them, it makes your muscles flex and contract very fast, giving you a humming sensation. i think that you have a big problem with your powerbook.

dodo_nutter · Jun 25, 2004, 05:39 AM

Yeah the AC would explain it but i thought the PB only delt with dc from the charger. The battery only gives out DC if im not mistaken.

Also im very worried if an AC current has enough power (high enough voltage im guessing) to travel all the way up my arms and trough my chest and my head.

Thanks for the opinions guy though cos im baffled!

d.fine · Jun 25, 2004, 06:57 AM

I always thought it was just the feel of the Al but now, after reading this post, I tried it with the PB unplugged, and it seems we have the same problem. I do only get it if I drag to top-side of my fingers over the Al, not if I do it with the under-side, or palm area. Even tough I don't really think it's a big problem, I mean it's not like I'm constantly dragging my fingers over the PB ...

wunderkind · Jun 25, 2004, 11:49 AM

I think the problem is caused by ungrounded plugs. I always get this cool vibrating effect at work where I use an AC adapter with US plug. Never on a battery or when I use an adapter with a grounded British plug at home.

First, I also thought that this is the texture of aluminum. Clearly it must be low-voltage current.

dodo_nutter · Jun 25, 2004, 01:45 PM

The english plugs are grounded arent they?? Or is the AC into the PB not grounded?

Ahh well hasnt killed anyone so i wont worry too much!!

vinster · Jun 25, 2004, 06:30 PM

Originally posted by dodo_nutter:
The english plugs are grounded arent they?? Or is the AC into the PB not grounded?

Ahh well hasnt killed anyone so i wont worry too much!!

Yes, as usual, the British standard for electricity is one of the best in the world. Not only is the default UK plug configuration earthed, it's also fused @ 13AMP. I would definitely look into your power source to make sure it's properly earthed and there are no problems with surges.

dodo_nutter · Jun 26, 2004, 08:48 AM

Well I'm almost certain that the whole house is earthed properly through the cold water pipes. My dad is an extremely thorough (i think thats how u spell it!) man and also an electronic engineer so i trust the earthing on the plugs.

It is really strange though.. surly nothing carrying current should be connected to the case by anything other than insulated materials which would mean even if there was something up with the grounding circuit then i still wouldn't feel anything.

Wow...i've found a problem thats got everyone stumped...i deserve a prize

d.fine · Jun 26, 2004, 11:41 AM

macaddict0001 · Jun 27, 2004, 12:22 AM

Originally posted by vinster:
It seems like some kind of low-voltage current. I read of others who have gotten mild shocks from their powerbooks when they're connected to a unearthed (ungrounded) mains socket. I have a rev b 15" aluminum powerbook and do not have this problem.

Have you tried plugging your computer in to various sockets around the house and see if there are any that don't give you the buzzing? Are you also plugged into a surge protector? If not, you might want to think about getting one.

yeah that could be but I don't think that different electrical sockets will solve the problem. apples power supply has a ground but only if you are using the extension cable to extend the power supply's range otherwise its ungrounded.

dodo_nutter · Jun 27, 2004, 07:50 AM

yeah that could be but I don't think that different electrical sockets will solve the problem. apples power supply has a ground but only if you are using the extension cable to extend the power supply's range otherwise its ungrounded.

AHHHHH!!... when use my PB in my room i always use the grounded extension cable, but whenever i get the weird humming im always downstairs n the plain power adaptor without the extension. So that could be it, i never looked at the plug adaptor thing to see that it wasn't grounded....just assumed it was.

Out of interest why isn't the plug adaptor grounded when the extension cable is, you would have thought they would ground both, and why have a metal pin on the plug if there isn't a contact!? they either should have put a contact in to connect up the ground OR put a plastic pin in.

Thanks for all your comments guys (and possibly girls!)

(btw how do you put quotes in when it says who the original poster is?? Do you have to use the button cos mine doesn't do anything, have to use the vB code)

macaddict0001 · Jun 27, 2004, 07:19 PM

Originally posted by dodo_nutter:

(btw how do you put quotes in when it says who the original poster is?? Do you have to use the button cos mine doesn't do anything, have to use the vB code) [/B]

You can choose the reply link

rag on a muffin · Jun 27, 2004, 09:39 PM

in case you dont know what taht looks like, it is

dodo_nutter · Jun 28, 2004, 01:30 PM

Originally posted by macaddict0001:
You can choose the reply link

Gottcha

Cheers!!