little lines flickering all over the place. Theyre mostly white, its only when I plug the laptop in to charge. I think AC is riding across the AC to DC converter, what could solive this problem?

 

Can you plug it into a different outlet? is anything else on your house running? Try turning off ceiling fans and TV's.

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None seem to solve the problem.

 

When my ceiling fan is on medium or high my TV becomes staticy. When my phone rings my TV (even if unplugged) will buzz, possibly picking up interference with it's CRT coils. When my computer turns on my plug in fan will slow down. Sheesh!

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Try getting an isolating transformer to see if its a ground loop problem.

 

I can feel a 'tingle' on my laptop sometimes, when ac adapter is plugged in, and I can measure up to 70 volts betwen the case and an earthed pipe.

 

That is actually quite normal, if I'm working on my laptop and touch a bare part of my partners skin (don't read too much into that !!) I can feel a 50hz tingle.

Strangely she can't feel it but its definitely there.

 

Sounds like a problem. Does this happen in locations outside your household as well? If so I would get a new adapter. If only in the house I would call an electrician...

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This is a common problem with a lot of laptop mains adaptors.

They quite often use capacitors between the live/neutral feeds and ground or create a virtual ground on 2 pin adaptors. I think they do this to reduce EMI.

There has been a few discussions on the PICList about this in the past,

http://www.reghardware.co.uk/2008/01...electic_shock/
http://gadgets.elliottback.com/2006/...lectric-shock/

 

Just done a test myself.

On my Fujitsu Siemens laptop if I am sitting on the sofa with it and hold one lead of my digital meter with my partner holding the other lead and the meter set on a 200v range, it registers just over 60vac.

If I measure between earth and the power supply -ve to the laptop I get 74 volts AC. If I measure between earth and the power supply +ve (tip) then I get a reading of 84.5 volts AC.

The test is strange considering I'm not actually touching any metal parts on the laptop. I assume the casing is slightly conductive.

 

No, it's to prevent a high static charge building up on the output, it's discharged back to the mains, but as there's no earth connection, it has to go to live/neutral - so you get a small leakage current back the other way, it's perfectly normal on class II devices.

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Nigel,
I first noticed this when I found I was illuminating LEDs (dimly) by just holding 1 leg. I had my Pickit2 plugged into a breadboard, at the problem stopped when I unplugged the AC adaptor
Jim