Yes knowing the shop concerned I strongly suspect the lack of earthing issue
mentioned elsewhere in this thread had come unstuck. Its very easy to get a
hum loop and feel that just unearthing one thing will fix it, but then
forgetting that no earth is possible not good either if anything went wrong
or just if a large capacitor is involved somewhere in the filtering.
Back when I was a spotty youth the trick we used to play on the girls
fitting components in the repair department was to leave a capacitor charged
up with a couple of hundred volts on their benches.

I'm sure you can imagine what tended to happen. Mind you there was one lady
who seemed to be immune to shocks. Probably had dry skin.
Brian

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This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Dave Plowman (News)" wrote in message
...
In article ,
Brian Gaff wrote:
Yes indeed, I was put of many moons ago from buying a Lecson system, you
remember the coloured sliders pre amp and the cylindrical power amp, as
touching the outside of the power amp while leaning on the radiator
gave me one heck of a belt. I did not enquire as to quite why this
happened but it seemed a trifle dodgy to me! Brian

You can get a small potential difference between earths grounded at a
common point when you measure well away from that point. Which is the
principle of equipotential bonding in a bathroom. But a large one means
something somewhere isn't right.

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*Filthy stinking rich -- well, two out of three ain't bad

Dave Plowman London SW
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