Dell Inspion 1300 - Screen Brightness

I recently dropped my Dell Inspiron 1300 causing the lcd screen to crack. After I ordered and fitteed a compatible new screen the laptop is again working fine. Except for one minor thing. Now, when I plug it in to the mains there is no observable difference in screen brightness from when it is running on battery power alone. This was never the case before. Also, when I try to increase the screen brightness by holding down the "Fn" key and the "up arrow" key, screen brightness does not gradually but continually increase but instead alternately brightens then dims then brightens etc...The same is true when I attempt to decrease the brightness.
The new screen had no place to attach an inverter so I simply taped the old one to the base of the new screen.
Does anyone have any idea what the issue might be? The machine is working fine but I could do with a little more brightness is all.
Thanks for you help...

 

did u check the power plan options in windows. Some of them make the screen stay at same brightness. Also check ur bios settings of the same relevance.
did u buy the screen from dell itself ?? Are u sure that this is a compatible screen ?? hope u didnt buy a low quality chinese spair part ?? can u specify the exact model of the new and old screens ?? did u install it urself or got it installed by a rep?? check the following guide to see if u forgot to plug in something
www.fonerbooks.com/laptop_6.htm

 

I had the same issues after replacing the LCD screen on my girlfriend's Inspiron E1505. I was wondering if changing the inverter would help solve this problem? Any luck with your notebook 'Crazyhorses'?