Samsung DVD home theather system ht-up30 unit only (mainboard trouble)+remote 

My main Samsung DVD home theather system ht-up30 bought from 2005 has trouble with mainboard. Two buttons are acting weird when pressed:
1.Power button (sometimes when i want to power off the unit,instead it will open the disc tray, but now I'm using the remote to do it)
2.Open/Close button (sometimes when I pressed the button instead it will change the function,same as previous I will use the remote to do it)