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MBP - Weird electric shock from case?

Message #1 - Posted 2007/08/21 - Darren Griffin - PocketGPSW...

Was in Greece last week and using the MBP with a three to two pin adapter when I noticed I was getting a very mild buzz type shock when I touched any part of the top case surrounding the keyboard. Removing the mains power or insulating myself (i.e. sitting on wodden chair and lifting feet) removed buzz effect.

Having now returned to the UK I can no longer replicate the problem so not sure what could have acsued it?

Darren Griffin
PocketGPSWorld - www.PocketGPSWorld.com
The Premier GPS Resource for News, Reviews and Forums

Message #2 - Posted 2007/08/21 - Rexx Magnus

On Tue, 21 Aug 2007 08:02:07 GMT, Darren Griffin - PocketGPSWorld.Com wrote:

Was in Greece last week and using the MBP with a three to two pin adapter when I noticed I was getting a very mild buzz type shock when I touched any part of the top case surrounding the keyboard. Removing the mains power or insulating myself (i.e. sitting on wodden chair and lifting feet) removed buzz effect.

Having now returned to the UK I can no longer replicate the problem so not sure what could have acsued it?

Dunno, but I get it a lot of the time in our house. I guess it's just a bad earth.

http://www.rexx.co.uk To email me, visit the site.

http://www.rexx.co.uk/runes/ - personal online rune readings

Message #3 - Posted 2007/08/21 - Peter Ceresole

Darren Griffin - PocketGPSWorld.Com wrote:

Having now returned to the UK I can no longer replicate the problem so not sure what could have acsued it?

Doesn't the MBP power supply have an earth pin these days (unlike the older laptop PSUs)? With these unearthed supplies and a TiBook, I would get a similar 'buzz' which I could eliminate by earthing the Mac.

Maybe the plug adapter you were using in Greece didn't complete an earth circuit, or (a nastier thought) the earth on the electrical supply in Greece was faulty?

Peter

Message #4 - Posted 2007/08/21 - Matthew Sylvester

Peter Ceresole wrote:

Maybe the plug adapter you were using in Greece didn't complete an earth circuit, or (a nastier thought) the earth on the electrical supply in Greece was faulty?

As Darren was using a 2 pin adaptor, there wouldn't be an earth connection. The buzz is nothing to worry about, it's usual for the output of many designs of switched-mode power supplies to float at a level above earth.

Message #5 - Posted 2007/08/21 - Ian McCall

On 2007-08-21 09:02:07 +0100, Darren Griffin - PocketGPSWorld.Com said:

Was in Greece last week and using the MBP with a three to two pin adapter when I noticed I was getting a very mild buzz type shock when I touched any part of the top case surrounding the keyboard...Having now returned to the UK I can no longer replicate the problem so not sure what could have acsued it?

Happens to me regularly with my MBP too, in the UK.

Cheers,
Ian

Message #6 - Posted 2007/08/21 - D

On Aug 21, 11:47 am, Ian McCall wrote:

On 2007-08-21 09:02:07 +0100, Darren Griffin - PocketGPSWorld.Com said:

?

Happens to me regularly with my MBP too, in the UK.

Cheers,
Ian

Mine too. Feels strangely alive. It actually seems to vibrate slightly when you run you finger lightly long case near the track pad. Only when on mains power, earth pin or not no matter where in the world.

Message #7 - Posted 2007/08/21 - Darren Griffin - PocketGPSW...

On 2007-08-21 11:10:49 +0100, Matthew Sylvester said:

As Darren was using a 2 pin adaptor, there wouldn't be an earth connection. The buzz is nothing to worry about, it's usual for the output of many designs of switched-mode power supplies to float at a level above earth.

That figures, I didn't have a travel kit but will invest in one, that should have an earthed two pin plug I assume?

Darren Griffin
PocketGPSWorld - www.PocketGPSWorld.com
The Premier GPS Resource for News, Reviews and Forums

Message #8 - Posted 2007/08/21 - Andrew Stephenson

Previously darren@pocketgpsworld.com
"Darren Griffin - PocketGPSWorld.Com" writes:

Was in Greece last week and using the MBP with a three to two pin adapter when I noticed I was getting a very mild buzz type shock when I touched any part of the top case surrounding the keyboard. Removing the mains power or insulating myself (i.e. sitting on wodden chair and lifting feet) removed buzz effect.

Having now returned to the UK I can no longer replicate the problem so not sure what could have acsued it?

I don't know about Greek electrical power regs but AIUI in the UK some years ago we went over to grounding Neutral at each property so it won't float above ground. Seems like the Greek arrangement lacked this feature, letting the entire computer become live when not grounded. A high-resistance leak from mains to case would be enough.

Andrew Stephenson

Message #9 - Posted 2007/08/21 - DBSnappa

D wrote:

On Aug 21, 11:47 am, Ian McCall wrote:

On 2007-08-21 09:02:07 +0100, Darren Griffin - PocketGPSWorld.Com said:

?

Happens to me regularly with my MBP too, in the UK.

Cheers,
Ian

Mine too. Feels strangely alive. It actually seems to vibrate slightly when you run you finger lightly long case near the track pad. Only when on mains power, earth pin or not no matter where in the world.

I'm sure this has been raised before. I know I experienced this and apparently it's caused by using the slide on plug for the PSU and not the mains cable with the plug on the end which IS earthed. Try it and see.

Message #10 - Posted 2007/08/21 - Darren Griffin - PocketGPSW...

On 2007-08-21 14:06:52 +0100, DBSnappa said:

I'm sure this has been raised before. I know I experienced this and apparently it's caused by using the slide on plug for the PSU and not the mains cable with the plug on the end which IS earthed. Try it and see.

Looks like that is indeed the cause, the slide on plug has no electrical connection in the slide whereas the cable does, an odd ommission? I'd never noticed this issue before but replacing the cable with the plug and there it is, the tingling across the case.

Darren Griffin
PocketGPSWorld - www.PocketGPSWorld.com
The Premier GPS Resource for News, Reviews and Forums

Message #11 - Posted 2007/08/21 - DBSnappa

Darren Griffin - PocketGPSWorld.Com wrote:

On 2007-08-21 14:06:52 +0100, DBSnappa said:

I'm sure this has been raised before. I know I experienced this and apparently it's caused by using the slide on plug for the PSU and not the mains cable with the plug on the end which IS earthed. Try it and see.

Looks like that is indeed the cause, the slide on plug has no electrical connection in the slide whereas the cable does, an odd ommission? I'd never noticed this issue before but replacing the cable with the plug and there it is, the tingling across the case.

Thought so :)

I always leave the cable plugged into the PSU now.

Message #12 - Posted 2007/08/27 - David Kennedy

On 21/8/07 10:11, Rexx Magnus wrote:

On Tue, 21 Aug 2007 08:02:07 GMT, Darren Griffin - PocketGPSWorld.Com wrote:

Was in Greece last week and using the MBP with a three to two pin adapter when I noticed I was getting a very mild buzz type shock when I touched any part of the top case surrounding the keyboard. Removing the mains power or insulating myself (i.e. sitting on wodden chair and lifting feet) removed buzz effect.

Having now returned to the UK I can no longer replicate the problem so not sure what could have acsued it?

Dunno, but I get it a lot of the time in our house. I guess it's just a bad earth.

I had it last week on an installation with an earth trip - I checked - using a G4, weird.

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