Install Alsa Mixer from the Ubuntu Software center (Applications → Ubuntu Software Center). Once installed, you will find the Gnome Alsa sound mixer in Applications → Sound & Video → Alsa mixer. Use it to push Capture level to maximum. Don't forget to check the Rec check-box under the capture slider. To avoid electrical noise slide the horizontal slider for “capture” completely to the right. The electrical noise seems to come from the lest side. (Check with sound recorder)

If you still experience some problems , you may also install the package “linux-backports-modules-alsa-karmic-generic” with the synaptic package manager and the internal microphone should work. (in the Ubuntu system menu under “System” > “Administration” > “Synaptic Package Manager”).

To use the terminal to achieve the same thing type :

 

On Ubuntu 10.04 and 10.10, this package doesn't exist. I was able to fix the problem by adding the following line to /etc/modprobe.d/alsa-base.conf:

Add the following line at the bottom of the file:

 

To use the internal mic with Skype, start Skype with

 

It can be done automatically by editind the Application menu:

- Right click on the Applications menu (on the upper left side of the screen) and select Edit menus

- Click on Internet in the right panel

- Select Skype

- Click Properties

- Replace skype by /bin/sh -c “PULSE_SERVER=127.0.0.1 skype” &

- Close and check if it works (you need to restart Skype if it was already up and running)