Ibook G4 the lcd when changed does have brightness issue

[qanda]This thread is about the Apple iBook G4 14.1" M9848LL/A. Click here to see full specs[/qanda]I recently tried to fix a broken LCD and after I went through 2nd company and making sure this one was the Correct LCD and made by Chi Mei which the only company that makes it I get low LCD brightness and I do not understand if this unit as well is not the correct one or am I forgetting something.
Thank you for your help.

Has the new replacement the exact same electrical capabilities and resistance as the original one? I guess they use other or inferior parts which would explain the difference in brightness of the lcd lamp.