Acer 5520 tracking mouse doesn't work 1- Used another tracking mouse from a used laptop ==> problem not solved. 2- Used my brain and checked the schematics Done Next measurement: Tracking pad connector on te motherboard has 4 Pins. - 5VS - TP_Data do it avoid 5V - TP_Clk do it avoid 5V - GND The TP_Data and TP_Clk have a direct connection with press buttons on the tracking pad and the SIO. I ve checked between the SIO and and the connector on the motherboard ==> connection was there. I ve checked between press buttons of the tracking pad and the connector ==> connection was there. The pressing buttons of the tracking pads need to go to GND when pressed ==> this was also OK. What it was remained to be check is the BIOS firmware or the SIO chip. I ve reflashed the BIOS first ==> PROBLEM WAS SOLVED. Download the bios here: ACER Aspire 5520-502G25Mi bios.rar File size:
