Pre-woned pda screen automatically shuts off

i bought a pre-owned handspring visor deluxe. at first i was using an ordinary triple a batteries. then the seller suggests to use alkaline batteries or rechargeable batteries, i did try both. when i used the rechargeable batteries, after a day or two of using it, the screen automatically turn off. the seller told me to try if the problem will persists if i will use alkaline batteries. i tried to use alkaline batteries, after awhile of using it the problem still there... the screen still turns off automatically though the timer is set to 3 minutes.

does the rechargeable battery did this to the unit? please help me. thank you.