DELL XPS 12 9Q33 internal microphone stopped working because of loose cable

The internal microphone of my Dell XPS 12 stopped working. Dell was not able to fix it in a remote desktop session. The support guy re-installed all possibly involved drives without success.

They sent me a technicial to replace the webcam unit.

What he found:

The cable which connects the webcam was loose. One of the plug was not fully plugged in, that was why the camera was still working, but the microphone wasn't.

How-HE-fixed-it:

The technicial removed the back cover of the LCD screen by removing the screws around it.
He unplugged and plugged in the cable connecting the webcam unit. Microphone was working again.

Here's the link to the service manual describing the procedure:
http://www.manualslib.com/manual/1070323/Dell-Xps-12.html

Where can i find drivers for Windows 10 on DELL XPS 12?

With the release of Windows 10, DELL released a couple of new drivers for the XPS 12 tablet / notebook:

You can find the drivers here:
http://www.dell.com/support/home/us/en/04/product-support/product/xps-12-l221x/drivers/advanced

Dell XPS12 Realtek Audio ALC3260 microphone and speakers not working after upgrade to Windows 10

I upgraded my DELL XPS 12 (9Q23, Late 2012)  to Windows 10 (from 8.1) and had an issue with the microphone and speakers being turned off after every start of the system. No sound, although the speaker symbol did not show it as muted.
The temporary solution was to mute and unmute the speakers to get it to work.

How i fixed it:
Dell released a couple of new drivers for the XPS 12 für Windows 10 under:
http://www.dell.com/support/home/us/en/04/product-support/product/xps-12-l221x/drivers/advanced

Here's the link to the REALTEK Audio driver for Windows 10 on DELL XPS12:
http://downloads.dell.com/FOLDER03160578M/1/Audio_Driver_GKHWY_WN32_6.0.1.7525_A00.EXE

The driver applies to:
Realtek ALC3223 High-Definition (HD) Audio

Realtek ALC3661 High Definition Audio

Realtek Audio

Realtek Audio ALC3234

Realtek Audio ALC3260

Realtek Audio ALC3620

Display connected to Dell U2414H on DisplayPort Out does only show cloned desktop / How to enable DisplayPort MST on U2414H / Three independent displays with Dell XPS12 with DaisyChain

I got a new Dell U2414H monitor. The plan was, to connect it to my Dell XPS 12 tablet with DisplayPort and connect my Dell U2412M to the DisplyPort out to get 3 independent displays working.
Setting everything in the first place only gave me a cloned desktop of the U2414H on the U2412M. Also my display settings on XPS 12 only showed me two displays instead of three.

How-I-fixed-it:
The problem was, that by default, DisplayPort 1.2 on the U2414H is DISABLED!
To get DisplayPort DaisyChain working, it has to be enabled manually in the monitor setup, as described in the user manual:
ftp://ftp.dell.com/Manuals/all-products/esuprt_display_projector/esuprt_Display/dell-u2414h_User%27s%20Guide_en-us.pdf#page=25

This is necessary to make the graphics card detect them as separate displays (they can even have different resolutions!).

The next step is, to enable three independen displays in the XPS 12 Intel HD 4000 settings, as descibed on the Intel FAQ "Configuration 3-Displays FAQ":
http://www.intel.com/support/graphics/sb/cs-033714.htm