Rpi2 turn off itself after some time

Hello

I moved to rpi 2 my micro SD card, but ever since, three days, I got the device shutting itself down.
Light show fixed red on rpi2. Wifi dongle lights goes off.
The past two night it happens near 10 pm.
Today I even started with a fresh installation on the card and now it is down since 40 minutes while I am away (4pm).
I keep using same PSU that suppose to supply 2000 MA.

Any log I can read for meaningful information?

Temperature was control at 50c.using my pi B it was 65c and no issue at all

What could it be?

Regis.

Ive read RPi2 had issues with flashing/bright lights. Have tried shielding your RPi?

I went to flash it with a cqmera while on, it does not stall, so its not that. The pi is revision 1.1, i guess the issue is address.
Back from work I notice a Warm smell, meaning that it over heat and stall, or the stall state makes it over heat. No idea, but now i back to my old Pi B.