Question How to check microphone hardware on Asus Zenbook UX330UA?

[itm]

The microphone on my Zenbook UX330UA has recently stopped working. The speakers are OK, but audio is not being detected by the mic. I've tried uninstalling and re-installing the Realtek audio driver from Device Manager, and also tried downloading and installing the latest version of the audio driver from the Asus website. Neither helped.
I've also tried booting Ubuntu (v16.04) from a USB stick, and the mic does not work on that either (although the speakers work fine).
Can I assume that the microphone hardware is faulty, or is there anything else worth trying?
Edit: I've just tried plugging in a USB mic and that works fine

 

[MJS WARLORD]

Remove the usb mic and go into sound settings , the layout changes often when updates occour and sometimes the update turns things off without you knowing , after an update my mic/headset stopped working because the update turned them off.

 

[itm]

I've looked in sound settings and the mic is correctly selected and seems to be enabled.

 

[MJS WARLORD]

if you can use an external mic i would say the mic firmware is ok , if the zenbook sound tab says its own mic setting is on then it points to a problem with the mic itself and could be something as simple a break in a solder joint that sometimes happens when poorly soldered items heat up.

 

[itm]

Are these things typically cost-effective to repair?