Xperia U switch off after inserting SIM

[sony_user]

Hi

My xperia u phone getting switched off if i insert a SIM card in it. i tried to restart it but it doesnot help. So i start it without putting up SIM card & take a backup of my contacts in laptop. i reset it to factory outlet & restarted & it works well for one day & again the same issue emerges. Can any body tell what can be the issue. Sony care people says its mother board is damaged . I just want to know if the motherboard is damaged how can a phone be ON without SIM for so many hours & even we can take pictures.... ..

[Alexander1]

Have you tried with different SIM cards in the phone? If the phone can't start with different SIM cards I suggest that you try to repair the phone software using PC Companion: 

http://www.sonymobile.com/update

And if that doesn't solve your problem you should have the phone examined by a service center. Please contact your local support for more information: 

http://www.sonymobile.com/global-en/support/contact-us/

[sony_user]

Thanks Alexander

Local service center guy said mother board is damaged but i put  it on observation by giving it to one of my friend & he putting different SIM card & it is working fine (almost three days) . but i guess on that SIM card there is no internet connectivity. So is it possible some issue with software can be possible????