Hi, I have a new board Mini8440, when I connect the mini8440 with a USB cable connected to my Laptop, I feel a mild electric shock on my Laptop. And this feeling is continuous and will be there until the board is connected to the Laptop. Please help ...
Are you the plug-pack that came with the mini2440? Are you running the laptop off a mains supply or batteries? > And this feeling is continuous and will be there until the board is > connected to the Laptop. I assume you mean disconnected? Do you have something else plugged into the laptop or mini2440? Like ethernet or serial cables?
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>>Are you the plug-pack that came with the mini2440? Yes I'm using the same plug pack >>Are you running the laptop off a mains supply or batteries? Just the laptop batteries I mean continuous because that vibrating or shock feeling will always be there until the board is disconnected from the power supply. Even if I switch off the black power switch on the board it will still have the same feeling No other cables are connected.
OK. Before any further tests I have no idea of the integrity of your mains supply, so proceed with caution. If it was me with my voltmeter the first test I would do is to measure for any voltage between the metal connector on the plug-pack and a known ground. Looking for leakage in your mains ground wiring. If you don't have a multimeter you could do the following: Confirm you still feel the mild shock on the laptop. The strength of this shock will probably depend on how well YOU are connected to ground. I wouldn't be stand on a bare concrete floor in bare feet doing these tests!! Disconnect the USB cable at the mini2440 end. Power switch off on the mini2440. Turn mini2440 upside down and touch one of the LCD mounting screws. Shock? Then disconnect the power pack and touch the metal outer on the connector. Shock? Get someone qualified to work on your mains supply OR another power-pack.
That is the same thing you can feel on some laptops when they are connected to their own charger, I'm not good at explaining it but it is quite normal and you can't do so much about it. Maybe a better 5V power supply could help but it might not even help.
Either the leakage specification for the power-pack is not low enough or the power-pack is not meeting specification. Either an isolation transformer or a power-pack with a real iron-core transformer in it should eliminate the problem.
Thanks Dave.. I will try these tests and come back.