keyboard very strange behaviour [closed]

Question

I have a USB keyboard which has a somewhat faulty wire. On shaking the wire, the USB keyboard sometimes gets disconnected or sometimes gets connected. This is normal.

But I have another very strange phenomenon with my keyboard: On switching on/off the tubelight in my room, I hear the USB disconnecting and reconnecting sound clip in my computer. This only happens when my keyboard is connected to my PC.

I do not have any light sensors in any device. Or is this due to some fluctuations in the voltage that the USB kb gets disconnected for a few milliseconds?

Answer 1

Dry joints and dodgy connections can act as diodes. Diodes can demodulate radio signals. That's basically how old "cats whisker" radios (crystal radios) used to work.

It sounds like the bad connection is picking up the radiated noise (EMI) from switching your light on and off and interfering with the USB data stream.

Get yourself a new keyboard, dude...

Answer 2

The connection to the shield (the part connected to the rectangular metal part of the USB connector- the "shell", rather than the small pins) is probably open at one end or the other.

The keyboard will probably continue to function, but will be more sensitive to electrical noise (what you are experiencing). It's probably resetting the microcontroller in the keyboard or affecting the USB PHY on your motherboard.

There are at least one, sometimes two, shields in a typical USB wire- the outer one surrounds the set of four wires, and an inner shield may surround the two differential data wires. Both are connected shell-to-shell from one end of the cable to the other.

Answer 3

It's all about you keyboard, from what I understand. If you have a keyboard that you really want to keep, you can still replace the USB head of your keyboards USB wire with a soldering gun and a spare wire (See my post: How to "frankenstine" wires?)

Also, the USB port of your computer might be silghtly damaged, try plugging other things in it and see what happened (I've never heard of sounds unintentionally coming from connected USB ports!).

Finally, you should just get a new keyboard... XD.