Laptop Brightness

Hello,

I have a customers computer. Dell Inspiron 1525 notebook. It had been dropped and the backlight was not coming on. I replaced the inverter and still no backlight. I replaced the LCD and now we have backlight. But the problem is the brightness isn't very good. When it's set on 1 or 2 it's medium brightness 3,4,5 it's very dim 6,7 it's medium-high and 8 is dim. It should go 1-8, 1 being the dimmest and 8 being the brightest. I have checked and reseated all connections. Is this an inverter problem? Is this a mainboard problem? Is this an LCD/Backlight problem again?

I have tested with both inverters but am wondering if the new one I got is bad. But they both do the exact same thing. I don't know if it has been shorted out by the bad backlight in the old LCD or what.

The mainboard could be causing this by sending bad signals am I right?

Could it be a problem with the new LCD? I have a hard time believing that because the brightness does switch it's just not switching properly. But if you think it could be a bad backlight then let me know.