Arch Linux

ziro360

Member

Registered: 2012-04-27

Posts: 30

USB Ports, strange bug

Hi, this is the stangest bug i have ever had. When i connect my tablet to the usb port on my Arch laptop the tablet touch screen starts giving false touch and pressing the wrong things.
At first i though it was the tablet fault but this only appends when the laptop is connect to a power source and on my other Windows/Ubuntu computer everything works fine.

Any ideas?

65kid

Member

From: Germany

Registered: 2011-01-26

Posts: 663

Re: USB Ports, strange bug

I also have this on my laptop when I connect it to a cheap third party power adapter I have. The touchpad behaves weird and if I connect my android phone via USB, its touchscreen behaves weird as well. When I connect my laptop to the original power adapter, everything is fine. I guess the cheap power adapter outputs a too high voltage or something (I'm not really into physics ). I don't think there is anything you can do about it besides trying another power adapter.

ziro360

Member

Registered: 2012-04-27

Posts: 30

Re: USB Ports, strange bug

But my power source is the one that came with the computer and this only happens with tablet not my phone.

Can this break my tablet?

ralvez

Member

From: Canada

Registered: 2005-12-06

Posts: 1,730

Website

Re: USB Ports, strange bug

It looks to me that you are connecting to what we used to call in engineering school  "a dirty power supply". That is to say a power supply that has poor filtration (line noise gets through) or that has bad filtering capacitors.

R.

defears

Member

Registered: 2010-07-26

Posts: 218

Re: USB Ports, strange bug

@ziro360
Plug in your laptop to the same outlet as your working computer and try it to rule out house wiring problems.
If it still does it, sounds like your laptop power supply has bad caps. Yes it will break your tablet because something is over heating.

@65kid
The cheap power adaptors put out a square wave, because they are electronic and not magnetic with the coils. It depends on what your device was made to use. Some devices behave better than others.

I had to get a $100 pure sine wave inverter for my laptop in my truck because the $20 dollar piece of junk made the screen scramble bad.

http://en.wikipedia.org/wiki/Sine_wave

ziro360

Member

Registered: 2012-04-27

Posts: 30

Re: USB Ports, strange bug

Well after testing some outlets in my house and in my girlfriend house the one that i generaly use for my laptop is the one that causes trouble. Could this mess up my computer? I switched my hard drive last month do to bad sectors.  Is there a way to fix it?

defears

Member

Registered: 2010-07-26

Posts: 218

Re: USB Ports, strange bug

Could be one of 3 things. Something on that same circuit is defective and causing it, (Eg. bad cable box) a loose connection can cause RF interferance or power on the ground wire.(Very bad)

Turn off breakers one by one and see if the problem disappears. Find out what's on that same circuit and unplug and turn off everything and see if it disappears. If you can't narrow it down, call an electrician.