X O Triangle and Square buttons not working‏

go to game stop and mabe its something wrong with either the buttons (faulty buttons) or the mother board has some loose solder to the buttons

I am having the exact same problem. I don't have a solution, but at least we have the exact same problem which means it's a repeating phenomena.

One more here! X button stuck. I've opened and replace the membrane board but the problem still. I must be something with the hard circuit board.

Try putting some rubbing alcohol on a Q-Tip or Toilet paper and rubbing it on the contacts on the motherboard. Normally what happens is over time the conductive material on the back of the membrane rubs off on the contacts creating a barrier preventing the membrane from making contact. Try that and see if it works.

I have checked the diagram and these buttons along with R1 and R2 are paired up with a common pin and a resistor, I have the same problem and will try to figure out where is this resistor located and try to change it, will post if succed.