My T43 zaps me!

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justlevine · #1 Post by **justlevine** » Tue Nov 13, 2007 1:58 pm

/Whenever I touch metal parts on my laptop (the serial port/parallel ports, thumb reader, etc) my laptop shocks me.
How can i prevent this from happening
(Im using my t43 notebook overseas, on a 220 outlet. The supplied adapter takes 110-240)

Stargate199 · #2 Post by **Stargate199** » Tue Nov 13, 2007 2:06 pm

I am going to guess the air where you are is very dry. when that happens, static electricity builds up easily. When you touch the thinkpad, you create a ground for that buildup to escape and you get zapped. Happens to me alot during the winter here in the states.

justlevine · #3 Post by **justlevine** » Tue Nov 13, 2007 2:12 pm

no, its not static electricity. If i hold my finger to one of the spots, i will continue to get zapped until i pull my finger away. I think its because too much current is running through the laptop, but i have no idea if 1. that is true, or 2. how to fix it if it is.

#4 Post by **jdhurst** » Tue Nov 13, 2007 2:24 pm

This has come up several times, and in response, I have done measurements using competent equipment.

A ThinkPad MUST be DEFECTIVE in order to have current on the case (including metal hinges and such like) that you could feel and that could be considered noticeable or harmful.

Just to belt and suspender: when the air is dry, and if I am not careful, I can raise a static shock on my ThinkPad (and on anything else nearby). I try attentively NOT to raise shocks on my ThinkPad by discharging somewhere else first.
... JDH

justlevine · #5 Post by **justlevine** » Tue Nov 13, 2007 2:29 pm

In that case, how do i fix it, even temporarily? or must i get in touch with Lenovo for a replacement?

#6 Post by **jdhurst** » Tue Nov 13, 2007 2:40 pm

I would certainly enter a service ticket with Lenovo and ask for advice.

The other thing I took for granted is that the AC adapter is working correctly. I have checked it as well and it doesn't have any extraneous currents. You could try a different adapter just to see if that is the cause.

When you can start to feel actual current anywhere, it is nearing a danger point. I have 30 Volts peak to peak with 5 amps availability across the rails of my model train in a dry basement. I feel nothing. So please do use care.

... JDH

justlevine · #7 Post by **justlevine** » Tue Nov 13, 2007 2:49 pm

I was afraid of that. Thanks for your quick reply.

#8 Post by **rkawakami** » Tue Nov 13, 2007 2:54 pm

Temporary fix: if you can, reverse the plug in the socket. This assumes you are using a symmetrical connection; two flat blades of equal size or two round pins, without any ground lead. And speaking of ground, if possible test the outlet you are using to make sure it is properly wired, with respect to how the ground/neutral lead is wired.

frankiepankie · #9 Post by **frankiepankie** » Tue Nov 13, 2007 4:19 pm

Is your wall socket grounded (do they call it 'grounded' in the USA?)

justlevine · #10 Post by **justlevine** » Tue Nov 13, 2007 5:06 pm

i reversed the plug, still getting shocked.
The wall socket is grounded, but the ibm charger cable only has 2 prongs. Isnt the third, usually located on the bottom, the one used for grounding?

Paul Unger · #11 Post by **Paul Unger** » Tue Nov 13, 2007 5:50 pm

Can I ask where you are overseas? Maybe that's not important, but I can confirm that in *any* country I have been in that uses 220V I have experienced the "zapping" that justlevine has mentioned. This includes: Solomon Islands, Australia, Fiji, and Papua New Guinea. And just for the record, it's hard to suspect static discharge when the ambient humidity is ~75%. Similar story here and here. In Canada (where I am currently) and the USA, where power is 110V, I have not felt this.

#12 Post by **jdhurst** » Tue Nov 13, 2007 7:54 pm

I have taken my T41 into Europe and plugged it into 240V mains. Still nothing. These things are well insulated. The DC from the adapter is low voltage and well insulated. The computer itself is well insulated. I suppose the High Voltage inside could leak out with a defect, but I think (I do NOT know) that it is relatively low current. ... JDH

Paul Unger · #13 Post by **Paul Unger** » Tue Nov 13, 2007 8:42 pm

I wonder if things are grounded better in Europe? I don't know--I'm an electrical 'tom thumb' . . . I do, however, find it's worse when I'm working barefoot on a concrete floor; wooden floor, not so much.

I believe you when you say "these things are well insulated"; I just don't know why mine (and a few others) "leaks" . . .

Amigaman · #14 Post by **Amigaman** » Tue Nov 13, 2007 8:58 pm

Do you get the same shock effect if you are running on battery, and the machine is unplugged?

JDH: The only reason you don't feel anything from your railway model is because your ~11VAC supply is too low a voltage to shock you. You are probably only getting 1mA or less. You only need 50mA or so to experience heart fibrillation. You are not going anywhere near 5A! (If you did, you would be definitely "feeling it").

Regards.

#15 Post by **jdhurst** » Wed Nov 14, 2007 1:06 pm

Amigaman wrote:<snip>
JDH: The only reason you don't feel anything from your railway model is because your ~11VAC supply is too low a voltage to shock you. You are probably only getting 1mA or less. You only need 50mA or so to experience heart fibrillation. You are not going anywhere near 5A! (If you did, you would be definitely "feeling it").

Regards.

DCC puts out 20 Volts Peak to Peak at about 10 KHz. A person draws current, so I was just noting that power supply has ample capacity with respect to current. I should have said 20V, not 30V.

The real point is that if you can feel an electrical shock, the voltage is getting rather high. I don't know what the actual threshold is, but I have a power supply that will put out 40 Volts (2 - 20 Volt supplies in series) and I commonly run it at 30 Volts and feel nothing.
... JDH

justlevine · #16 Post by **justlevine** » Wed Nov 14, 2007 1:15 pm

so I am in israel, the outlets here run at 220V.. how much the maching drawing (or what not), i dont know how to check. I do not have this problem running on battery, or even all the time using a plug. However, it does occur often.

#17 Post by **rkawakami** » Wed Nov 14, 2007 2:32 pm

While there may indeed be something wrong with the laptop, you can take the following precautions if you continue to use it plugged in:

- insulate yourself from earth ground as much as possible. This means no sitting on metal chairs, placing bare feet on concrete or touching any metal which is in turn, plugged into a wall outlet when using the laptop.
- if you do continue to receive shocks/vibrations/tingling, note what your entire body is touching; some part of your body is in contact with ground otherwise you would not be feeling anything. Also, note what outlet you are using when this happens. If it's always a particular outlet, or house/building then it's possible that the AC wiring is wrong.
- if available, try another AC adapter, duplicating the same operating conditions; power supply may be defective.

To answer your earlier question, yes the third pin/prong is ground. I don't know how the 220VAC wiring is done but since the AC adapter is supposed to be delivering isolated DC power you shouldn't need to be using the ground connection. For example, I am using a combo AC/DC power supply with this X22. It has the standard two-blade AC plug. When the laptop is being powered off of the adapter, I can measure 60VAC between the metal portions of the laptop to the AC outlet's ground screw. The current is only 33uA; not enough to be felt. Reversing the AC plug, the voltage drops to 50VAC and the current lowers to 23uA. So there is some difference. You're never going to feel anything when the AC adapter is disconnected from the laptop; you have removed the source of the errant current.

justlevine · #18 Post by **justlevine** » Wed Nov 21, 2007 3:08 pm

well, i got my response back from IBM... turns out they want me to pay or call a toll-free number (which i cannot do from this country)...
@rkawakami: i have done most of what you suggested, and it has helped for the most part. It turns out not to be a particular outlet, and i have no other adapter available to test.
Also, I have noted that my computer is less likely to zap me when it is not connected to other hardware, specifically my targus universal adapter, and my maxtor 100g external harddrive (both of which require external power sources -despite the adapters allowing each for up to 240). However it still has not stopped entirely.
Any other suggestions to get this to stop completely?
(also, is it unsafe to use the computer even if i am preventing myself from getting shocked by the methods described above?)

#19 Post by **rkawakami** » Wed Nov 21, 2007 4:27 pm

Hmm... if the other equipment you are connecting to the laptop has their own grounding problem then I supposed that could be passed along through the connectors (USB, PCMCIA, etc.). About the only way I know of isolating the problem would be to use a voltmeter and measure the voltage between the metal parts of your laptop (screw heads, parallel port screws, etc.) and earth ground. Earth ground can simply be any exposed metal on an electrical appliance.

Run just the laptop with the AC adapter and measure the voltage. Make sure you are using the meter in the AC voltage range of at least 300V. If there isn't any appreciable voltage, plug in one of your peripherals (also connected to AC power) and re-measure. If you see a substantial increase in the voltage, you've found the problem item. You can then try reversing the power plug on that item, if possible, and see if the voltage changes. I'm ignoring the current component of this problem as that can be a little bit harder to measure safely with a meter. The best way that I know how to do that is to get yourself one of those "screwdriver circuit testers" like on this page:

http://www.electricalbasics.com/acatalo ... ester.html

and see if the light turns on. The other choice that I can see is to call in a certified electrical technician and have him/her check everything over.

Is it safe to continue using your laptop? Probably, however I would not let it come into contact with ANY metallic surface when it's plugged in until you determine what the problem really is.

#20 Post by **richk** » Wed Nov 21, 2007 5:10 pm

Do you have an outlet with a ground-fault interrupter? (The kind people have in bathrooms or kitchens) Se if it trips.

#21 Post by **jdhurst** » Wed Nov 21, 2007 6:38 pm

I don't wish to appear to overdoing this, but I was reading the instruction manual for my new(ish) digital voltmeter because I want to measure 10 Khz AC Current (Model Railroad DCC). In the instructions, they noted that the DVM will show an alarm if voltage at the test probes is over 24 Volts. I see the alarm at house voltage (duh!), but their safety factor is 24 Volts. I cannot feel 24 volts, even if I wet my fingers. So take care if your ThinkPad is shocking you. Both the current and the voltage are somewhat high if this is happening. ... JDH

dcouzin · #22 Post by **dcouzin** » Wed Nov 21, 2007 7:42 pm

You can use Skype to "phone" toll-free US numbers from anywhere, free.

Gadgo · #23 Post by **Gadgo** » Sat Nov 24, 2007 11:58 pm

I am in Australia (240VAC 50Hz) and have been using a T43 for 2.5 years, I have never experienced an electric show from the unit in any situations. I also travel extensively throughout south east asia and have experienced a number of other AC supply systems including 110V AC 60Hz (Similar to US) again nothing like this.

I am an electrical engineer and would suggest that if you are receiving shocks from your laptop when it is plugged in to external power then there is most likely a fault with the AC adapter.

I recommend having an electronic technician measure both the AC and DC potential from the laptop to earth to determine if any dangerous voltages exist. If they do please replace the adapter.

The laptop is powered exclusively by DC which it obtains from the battery, the AC adapter (charger) is an autoranging unit that operates with an AC input between 100V and 240V @ 50 to 60Hz this covers most places around the globe. The adapter output is 16VDC @ 4.5 amps. It is unlikely that the laptop internals will be the root cause of your issue.

It is possible that the isolation between the AC (input) and the DC (output) of the adapter is not as it should be. therefore I would suggest, if you can lay your hands on another charger, trying a different unit and determining if the condition still exists.

I currently use 3 different AC adapters on my T43, the unit that was supplied, another from an earlier model IBM and a Dell unit from 3 or 4 years ago that has similar characteristics and the same plug into the laptop. (just check the adapter label for spec and ensure that the DC positive pin is the centre of the plug with DC - ve (GND) being the outer of the coaxial plug, easy to check if you have a voltmeter.

justlevine · #24 Post by **justlevine** » Sun Dec 30, 2007 7:40 am

So i followed some of your suggestions, and it turns out that it isnt my t43 itself that is turning itself into a cattle prod. It seems to mainly be caused by things that plug into my usb port that require an outlet for their own power source (external harddrive, port replicator), but also sometimes by usb-powered devices (mp3 player, usb speakers, (rarely) external mouse).

Any suggestions?[/i]

#25 Post by **Harryc** » Sun Dec 30, 2007 12:06 pm

If you have equipment connected to many power outlets, then try to connect them all to one grounded extension cord (power strip) and then plug this cord to one grounded outlet. Include your T43 and all connected devices on this one connection. The outlet itself should be tested for proper wiring. You can purchase inexpensive outlet testers at a local electronics store or home center.

http://www.shopping.com/xFS?KW=outlet+w ... er&CLT=SCH

#26 Post by **richk** » Sun Dec 30, 2007 1:37 pm

I would like you to try all the devices (one at a time) with a ground-fault interrupter to make sure nothing is dangerous.

Tim M · #27 Post by **Tim M** » Sun Dec 30, 2007 6:43 pm

Being an engineer myself, I agree with what gadgo has said. I have lived in the UK for ~1 year and traveled to Europe and Asia without any "shocking" by the ThinkPad except when it was caused by grounding out electrostatic charge accumulated on my person (which should be avoided with a laptop). I find it unlikely that high voltages are being generated by your ThinkPad's power supply given it's design characteristics.

justlevine wrote:So i followed some of your suggestions, and it turns out that it isnt my t43 itself that is turning itself into a cattle prod. It seems to mainly be caused by things that plug into my usb port that require an outlet for their own power source (external harddrive, port replicator), but also sometimes by usb-powered devices (mp3 player, usb speakers, (rarely) external mouse).

Any suggestions?[/i]

I'd also recommend connecting all the peripherals (and the laptop) to an extension cord plugged into a single outlet; you may be having some sort of ground loop issue due to poor wiring at your location. I'd also heed the suggestion of checking each peripheral separately for faults.

dcouzin · #28 Post by **dcouzin** » Mon Dec 31, 2007 10:48 am

If justlevine says he gets shocks ONLY when he's using the AC adapter, then since a properly working AC adapter should only provide 16 VDC to the laptop, hardly different from the battery, isn't his AC adapter necessarily the culprit?

Tim M · #29 Post by **Tim M** » Tue Jan 01, 2008 12:28 pm

^ If you review the thread, it seems that the OP's problems are associated with separately-powered peripheral devices being plugged into the ThinkPad's USB ports, suggesting the issue may not be with the laptop's AC adapter.

My T43 zaps me!

My T43 zaps me!

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