Need help to fix the contrast of iPAQ 1945

Hello there,

I just joined this great forum and look forward to get help and to be helpful as well.
Installed a new backup batter in my device and seems I messed up with the contrast adjustment. The screen looks 100% normal for few seconds then starts fading out and it becomes hardly readable. Every thing else works fine.
Can some one help me to fix the contrast problem please??