odd problem: getting electric shocks...

S

sebhoff

Registered
I have an odd problem and I wonder whether anyone can help.

I've changed two things to my Powerbook G4/550 (with Combo drive): the country I'm in right now (Malaysia rather than Switzerland) and the hard-disk (a 60GB IBM Travelstar rather than the original 20GB one).

The problem: When the computer is connected to the power supply, I get a small electric shock when I touch it in two places at the same time (for example while typing when my underarms rest on the casing of the Powerbook.) The shock is not very strong, a bit like when I pull a hair from my arms... It's not a one-time thing but occurs again and again after a few seconds.

This happens regardless of whether the computer is running or not. It does *not* happen when the computer runs off the battery alone. I have no idea whether it would also have happened before I changed the hard-disk because I only ran off the battery after arriving in Malaysia... And I don't really want to change the HD again just to try. ;-)

Someone has told me that it has to do with the way Malaysian sockets are grounded - but I'm a bit doubtful about that. The fact that it only happens when I touch my PB in two different places means that there is a power differential somewhere within my computer - doesn't it?

I've re-opened my powerbook and checked whether the Mylar sheath is correctly placed around the new hard-disk - and it seems to be so. At least I didn't see anything which looked suspicious.

If this is a Malaysian problem - I can live with it for the next 2 weeks. If not - what should I do? Is it anything that could seriously harm my powerbook? People I've spoken to in shops which sell Apple computers over here tend to know nothing about things like that - and the closest official Apple service center is (I think) in Singapore....

I'd appreciate your help - many thanks in advance!
Sebastian
 
Don't worry about the powerbook, there's always another. Worry about you. Sure, it's only little shocks now, but it only takes one big shock...

The fact that there's a voltage difference on the powerbook, only when plugged in, sound like it would mean there is something wrong with the (plugin) power supply. Malaysian current thing doesn't sound right, somehow. Maybe, since it only happens when plugged in, it would be safer to plug the computer in when you aren't using it, let it recharge, and unplug it before you use it - can't be too cautious.

Observe the physicist's rule: when dealing with high voltage equipment, put one hand in your back pocket. This means any shocks you get only travel within your arm, so the worst you can do should be to ruin the nerves in one arm. A big shock that travels between two hands will go via your heart; you don't want that.

Note that I am no expert in any of this. Still, get it looked at as soon as you're somewhere where there's competent computer techs.
 
As you already suggested, it has to do with the power plug and, further, with the way PowerBook power supplies work. Contrary to older desktop power supplies, they do not have a galvanic seperation between the input and output, therefore some parts of the housing have a more or less direct contact with the electrical power plug of your flat. This alone normally does not lead to the described effect, since the gound and neutral pin in the plug a coupled, i.e. eliminating the voltage difference between them. Now, in certain countries (and I have been in such, too), the neutral lead is coupled to the ground only further away and not directly in or close to the plug. Due to line
capacities and inductivities, this can lead to quite a difference in voltage between these to leads at the power plug (I've seen up to approx. 100 volts). Due to the way this voltage difference in generated, the resulting amperes are very little, normally in the area of a few microamperes, which should at most lead to a slight sting, which is harmless. If you can feel more or even pain, I'd definately let check the power supply and the power plug for defects or wrong wiring!

Hope this helps,
Christoph
 
Originally posted by nadig
Hope this helps,
Christoph
Click to expand...

Yes, thanks!
I suppose it'll stop when I get back to Switzerland...
I've done a search on the net and it seems a few other people in hot and humid places (particularly Singapore and Hong Kong) have had the same problem.
"Merci fuer'd Hilf" - best,
Sebastian
 
That is funny...I am from america on an internship in Switzerland and just last week my tibook started to give my electrical shocks also. It was only for one night though. Wierd.
 
Originally posted by jaybeekay
That is funny...I am from america on an internship in Switzerland and just last week my tibook started to give my electrical shocks also. It was only for one night though. Wierd.
Click to expand...

Positively no more shocks on my side since I got back from Malaysia...

While still there, I went into an Apple shop and enquired about the electric shocks I was getting. The owner of the shop just smiled and said "9 out of 10 customers come back with the same question - yes, it is normal and yes, it will probably go away when you are back in Switzerland". He said he had informed Apple Malaysia about this but didn't think they would do anything to solve the problem...

Sebastian
 
I had the same problems with my Apple II , way back in time... The 2 screws under the keyboard where "live" .
 
You must log in or register to reply here.
Back
Top