Audio output connector - Only the right earplug have sound?
 

i have a N900 that works perfectly well.
Mi brother though, connected his N900 headset to the audio jack for the first time today. and it turned out the left earplug didnt output any sound. we tried reconnecting several times and restarted the phone without success. I tried his headset on mine - and it worked flawlessly.

Is this a common defect that the N900 audiojack only provides sound on the Right channel?

Is there an easy fix besides returning it for warranty repair?