[ProximaCentauri]

Hello, head-fi members. I am quite new to the forums and this will be my first thread.
So to the point, I purchased a pair of K240S on the 26th of May, this year. They've been doing great, no problems with them at all, but today, something rather strange happened, the sound on the left ear-cup disappeard. Don't get me wrong, I'll exchange these possibly tomorrow, but I really want to know what the problem is. I've take doff the ear pads to see the drivers and they're all right, no cracks or anything, both look the same. I moved the cable around, did bends and other stuff, but that didn't seem to bring back the sound. I'm confused because I've been taking care of these a lot, I never did anything wrong with the cable or anything. It happened when I was switching from my iPad back to my computer, when I switched to the computer the sound disappeard, I tried it on all my devices but nothing worked. I want to know, to prevent future damage, since I've heard of them lasting for 6 years, and mine broke in 1 month. Now I know this post looks like a mess, but I am really tired and not worried about it right now. 
Thank you for your help, and have a good day 

 

[NA Blur]

It is probably a driver on your PC going to mono, but if that is not the case it could be the jack plug.  Does it have an adapter on the plug?  If so try it with another adapter or remove the adapter entirely and try it on another device.
 
Sometimes debris can jam the driver movement.  This is typically of hair or a large piece of dust.  Gently blow out the driver area or vacuum it out ( gently ) and see if that helps.

 

[ProximaCentauri]

I actually tried blowing out any dust, but it didn't help. You know when you plug in headphones and you hear the noise? (THUD THUD THUD)
I hear that only in the right ear too. I tried it on multiple divices with the same result. I don't have a possible way of trying the 6,3mm adapter atm. 

 

[reeshahn]

Quote:

I actually tried blowing out any dust, but it didn't help. You know when you plug in headphones and you hear the noise? (THUD THUD THUD)
I hear that only in the right ear too. I tried it on multiple divices with the same result. I don't have a possible way of trying the 6,3mm adapter atm. 

 
It sounds like problem is caused by the jack. In some rare cases (and I really mean rare) during plug in /out action some high electric current can harm the headphone but I saw it happening only once in my life.

 

[NA Blur]

It does sound like a dead driver or bad wiring / solder.