How to fix this problem ?
 

I got a Samsung Captivate 2nd hand with firmware 2.3.3. Baseband version is I896UXKH2. I don't know why it will shut down by itself and I need to turn on to reboot it.

Temp fix is to use an app called Keep Alive

Please help

Would help what solutions you've tried. Battery issue maybe?

I've noticed the same issue with my i896 Captivate. Random shutdowns. Not reboots, just straight phone is off when I go to use it.

It hasn't done it in several days, and happened with a lot of frequency over a 3 day span about a week ago, and it's happened maybe once every 2-3 days since. Not for 3-4 days now though.

No real solution that I could google up either.

I have the same situation as yours. Need a permanent solution to fix it.

try a factory reset?

maybe root it and flash a new rom?

does this happen when its plugged into a charger?