Default [Q] GT-P1000 7" brightness not adjusting.

Hi all

Samsung Tablet 7" GT-P1000 was dropped and it would not power except the 4 four control buttons on bottom.
Changed display and digitizer (touchpad) and working o.k.

However brightness settings adjustment is not working both auto adjustment *and* manual adjustment. After booting, a slight variance is seen during manual adjustment but it still saves on bright. Second try no variance is seen during or after manual adjustment. Thus brightness remains fixed (battery is drained especially when reading and it is very uncomfortable to use).

Flashed from Froyo to Gingerbread firmware 2.3.6 to no avail.

Any suggestions please?

thanks and regards