lcd show weird colors

Hi there everyone,

''So i repair for living mostly i find by myself what the problem is but with this one i got no idea what i could be.

''

so i got an client with a Samsung tab Model; GT-N8010 he come over with this tablet showing strange colors (like the colors are negative) on the lcd.

no problem i replace the lcd , everything worked perfect colors are perfect.

after 2-3 weeks client comes over again with the same issue, ofcourse hes little bit mad because he payed the repair.

thing i hope you can do answer for me:

''-can it be from dropping the tablet on ground?

-could it be lcd cable?

-is it an hardware/software problem?

-did someone experience this ever before?

''

thing i tried:

'''-factory reset

-soft reset

-try to put negative colors on to see ( that even worse)

'''

sorry for my langue (im dutch)