Unresposive touch screen - screen problem ruled out

Hi there,

I have come across a strange thing with the phone of my boss.

He told me from one moment to another the touchscreen became unresponsive.

I took the phone, dissassembled it, tried with another screen only with cables connected, no shielding bracket, worked. Then a cleant the socket and the plug with isopropanol of the original screen and tested it, still without the shield, it surprisingly worked. I reassembled the phone with the shield, switched it on, no touch again. I tried with the other screen assembled, doesn’t work. My ideia is the touch ic, isopropanol might help but after evaporating, the problem comes back. I don’t think it can be anything with the screen.

Any thoughts from you?

Thanks.

Tamas