just sharing..
last month i sent my xperia z for repair.

first i notice that sometime i cannot hear what the other person on the phone is saying. i thought line problem but , after asking people around me and calling my service provider, seems like i am the only one having the problem. it become more frequent after some time. confirm the internal speaker is faulty when i can hear using loudspeaker during call. still work sometime after restart and light knock on the phone back.

but i didn't send my phone for repair asap as i got no time and i know it will take long time . then another problem arise, my phone reception become poor. keep losing signal, and become worst the next day. can only receive signal when i move close enough to communication tower. of course my phone become hot and battery drain become super fast because its trying hard to get connection.

then only i send my phone for repair and it took me 6 weeks to receive it back. i hope no more problem after this, my warranty only left 2 weeks.