Feeling electric current off of T42 case

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memoboy
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Feeling electric current off of T42 case

#1 Post by memoboy » Mon Aug 30, 2010 11:46 am

I periodically feel sort of an itchy electric current when I have the laptop against the skin of my lap or when i have my hands touching the metallic sides while using my T42. I was curious if anyone else feels the same thing when their skin is in contact with the metallic bottom or sides.

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Re: Feeling electric current off of T42 case

#2 Post by rkawakami » Mon Aug 30, 2010 11:39 pm

Other people have reported such a sensation. My suggestion would be to reverse the AC plug at the adapter, if possible, and see if that helps. The laptop should be isolated from the AC mains but there can be a problem with the AC wiring (improper ground or hot and neutral reversed) or the AC adapter is no longer isolated. You can also take an AC voltmeter and see if there's any significant voltage between the metal case of the laptop (mounting screws of the VGA or parallel port) and house ground. There may be 10's of volts (10-40) indicated, which is probably okay. If you read 220VAC, then there's something drastically wrong. You really need an AC ammeter (and a way to limit the current) to tell if there's a shock potential but not many people will have that kind of equipment laying around the house. Generally speaking, it's the current that will kill you, not the voltage.
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Re: Feeling electric current off of T42 case

#3 Post by poshgeordie » Tue Aug 31, 2010 9:03 am

I wonder if this only happens with you're using an AC adapter with two wire (live & neutral) mains cable, compared with the 3 wire cloverleaf mains cable with also includes and earth.

@RW - the phrase you're looking for is "It's the volts wot jolts :shock: but the mils wot kills :flame: "

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Re: Feeling electric current off of T42 case

#4 Post by richk » Tue Aug 31, 2010 10:18 am

If you have a GFI (the kind of plug found in kitchens and bathrooms on newer homes) plug it in there. The GFI will trip if you have a problem.

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Re: Feeling electric current off of T42 case

#5 Post by irus » Fri Sep 03, 2010 4:51 pm

i had the same problem. i got my home wiring checked , grounds were missing in the house at places and neutral/hot were reversed at many plug points.

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Re: Feeling electric current off of T42 case

#6 Post by Rick Aguinaldo » Tue Sep 07, 2010 1:03 pm

I had the same experience once but on an older Thinkpad. It was caused by a leaky (nicked) inverter-to-CCFL cable. If you run the T42 on battery only and still gets the sensation, chances are high that a part of the back light inverter output circuitry (cable with insulation damage for example) could be in contact with the metal frame of the lcd panel.

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Re: Feeling electric current off of T42 case

#7 Post by loyukfai » Wed Sep 08, 2010 1:18 pm

rkawakami wrote:...but there can be a problem with the AC wiring (improper ground or hot and neutral reversed) or the AC adapter is no longer isolated...
Seems to be the cause in my case. Unfortunately I haven't have time to get it fixed, yet.

Cheers.

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