9800 strange problem blank

[coast2coast]

hi friends im having a problem with a 9800 when you slide the phone up without the back housing it displays perfect but bottom keypads dont work.
then if you insert the back housing with the slide up it displays blackberry for about 5 secs and goes off,if you slide it back down the phone is on and displaying normal.in this process the phone does not switch off every time you slide it up its blank slide back down its normal.
i tried another board on the flex and it works hundred percent.

please advise me further with a solution thank you

[ALI1]

Originally Posted by coast2coast

hi friends im having a problem with a 9800 when you slide the phone up without the back housing it displays perfect but bottom keypads dont work.
then if you insert the back housing with the slide up it displays blackberry for about 5 secs and goes off,if you slide it back down the phone is on and displaying normal.in this process the phone does not switch off every time you slide it up its blank slide back down its normal.
i tried another board on the flex and it works hundred percent.

please advise me further with a solution thank you

u shod replace the flex cable if same then replace the small crystal ic (behind the charger connector) it'll be done