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OzAl · Jul 30, 2003, 07:18 AM

This is going to sound weird, but then it _is_ weird. So here goes...

My wife noticed that if she touched my ears lightly while I was sitting using my pb17, my ears were vibrating slightly(!). If she then held onto me and someone else touched her ears lightly, the vibration was transferred to her.

After further investigation, I have discovered the following, which occurs when (and only when) the AC adaptor is plugged in:

- if I earth myself (e.g. hold a large metal standing lamp), and rub my hand lightly across the surface of the pb17 palm rest, I can feel a slight vibration, somewhat like static electricity.
- as soon as I let go of the earth, the static electricity is transferred to me (and my ears)!

This is endlessly repeatable. It's not something that goes away once I've earthed the pb17. I've noticed the static electricity effect before on occasion, but never investigated it further before now.

Do any other pb17 owners experience the same behavior? Or do I have a "leaky" power adaptor?

BTW, my pb17 is plugged in to a 240V power source; the same phenomenon may not be observable on 110V power.

Regards,
OzAl

DigitalEl · Jul 30, 2003, 07:39 AM

Did you remember to take your pills today?

OzAl · Jul 30, 2003, 07:54 AM

Originally posted by DigitalEl:
Did you remember to take your pills today?

Don't know about you, but I took the red pill. (If you haven't seen the Matrix, don't bother trying to make sense of that).

Believe it or not, this was a serious post. Tomorrow I'll be showing up at the nearest thing we have locally to an Apple store to demonstrate it.

In the meantime, if you have a pb17, why don't you share with us if you've experienced the same thing. If you don't have a pb17, feel free to make some more wise cracks, as long as you make an effort to make them entertaining.

kbdog · Jul 30, 2003, 08:16 PM

I've noticed this effect on appliances but not on my pb17. You can actually run your hand over some ( an electric frying pan works well) and feel the a/c cycles; 110v @ 60 hz here in Canada; 240v @ 50 hz in Oz.
I think it is a tiny residual current leaking through the neutral wire but I could be wrong.
All trace of the effect vanishes when the device is unplugged.
You're not wrong mate!

DVD Plaza · Jul 30, 2003, 10:03 PM

I've noticed my partner gets annoyed with me when I'm working on my PowerBook whilst she is making dinner - not sure if the static is perhaps leaking through the air and causing her frustration, or that I'm not helping her...

On a serious note though, I can feel a static charge with my 15" however my 17" does not - which is expected given the 17" (and 1GHz 15") are now grounded.

DVD Plaza · Jul 30, 2003, 10:09 PM

Originally posted by OzAl:
Or do I have a "leaky" power adaptor?

That shouldn't be the case - the 17" power adapter is designed to shut off if it detects anything weird with the power and/or ground. Infact it's a little too sensitive - the airconditioner in my home often causes my 17" power adapter to cut off.

buddy1065 · Jul 31, 2003, 04:17 AM

Doesn't the adapter come with some sort of grounding dongle? Almost sure I heard it does. Go look in your 17" box or read the manual. I have read posts where this dongle was attached and no more problems.

OzAl · Jul 31, 2003, 10:40 AM

Originally posted by buddy1065:
Doesn't the adapter come with some sort of grounding dongle? Almost sure I heard it does. Go look in your 17" box or read the manual. I have read posts where this dongle was attached and no more problems.

I'm not aware of any grounding dongle. The adaptor has a piece that slides on or off, but there's no ground connection. My adaptor is also sensitive, BTW, as per DVD Plaza - it often shuts off when I turn off my bedside lamp.

Anyway, this isn't a one-time static buildup, it's an ongoing tiny residual current, as kbdog described it earlier. So I got a colleague who's an engineer to check it out. He also observed the phenomenon, so got hold of a digital multimeter.

The bottom line is that when the power adaptor is plugged in, you can measure 90-95 Volts AC on the case(!). Unplug the adaptor and it still shows about 10 VAC. Only very low current, though (0.05 amp).

Now that I have some objective evidence, I'll simply contact Apple.

Thanks to all who offered comments and suggestions.

OzAl

stevesnj · Jul 31, 2003, 06:47 PM

I had the same static problem and started using the 3 prong cord instaed of the 2 prongand no more static.

OzAl · Jul 31, 2003, 08:22 PM

Originally posted by stevesnj:
I had the same static problem and started using the 3 prong cord instaed of the 2 prongand no more static.

Dang! You're both right about the 3 prong cord. I'd put it away and never used it, so I forgot about it. But it does appear to solve the problem.

The painful thing, though, is that I have 2 prong power cables dotted all over the place at home and at work so I can simply plug the AC adaptor in. Now I'll have to lug the 3 prong power cord everywhere.

Thanks for your help - the forum came through again (and saved Apple some time!).

OzAl