Help if i lock tablet, it turns off, PLEASE HELP!

[Android Question dodo]

Hello,

I'm IT technic and my boss gave me simple, but after long time very hard quest...

His friend bought this machine: http://www.asus.com/Notebooks_Ultrabooks/ASUS_Transformer_Book_Trio_TX201LA/

asus transformer trio tx2001l
and its somehow bugged or something. If i have tablet in my hands, its powered. Now i click on the button behind the tablet, to LOCK the screen (just 0,3sec click to lock it). Screen got locked, now i can unlock it, but if i will wait around 10 seconds, the tablet turns off and i have to hold the button for longer time, so i will start up. Battery is full.

please i need your help, i already tried to download this firmware 1.10.6 version, WW (worldwide) version, as this tablet is WW version, but it didn't help.

http://www.asus.com/Notebooks_Ultrabooks/ASUS_Transformer_Book_Trio_TX201LA/HelpDesk_download/

OS: Android, Firmware - 1.10.6 WW

then i managed, maybe lower version could help, so i put the tablet into factory setup, and tried lower version 1.10.5 but it didn't help too...

I also tried to download apps for not allowing my tablet to go into sleep mode, didn't help

im seriously lost, please help...