There are many modules in IO that manage different functions. io chips are often damaged for various reasons.
The simplest judgment method - functional measurement method, as long as the working conditions of IO are met, it should work normally, otherwise it is regarded as damaged! Take the simplest example: the board in which IO participates in triggering. When IO receives PWR_SW(press the switch), it should send a PWRBTN# to Southbridge. If the IO receives the switch signal and does not send PWRBTN# to the South bridge, the IO is damaged.
Substitution method. Use the heat gun to change the same model, the fault is solved, indicating that the original io is damaged. This method requires a certain level of welding and equipment, and there are spare parts of io
Measure pin by pin. You need to check the information of the io in advance. W83627HF is used as an example to illustrate the process:
61# 5Vsb standby voltage
70# 3.3V standby voltage.
72# 5V standby voltage, low level after triggering
74#,76# Battery voltage input (3V)
12#, 48#, 77#,97#, 114# 5Vcc(core voltage)
28# 3.3Vcc (Core voltage)
Any of the above foot to the ground short circuit can generally judge IO bad.
31# -37# Printer management
58#, 59#, 60#, 62#, 63#, 65#, 66# Mouse and keyboard management
If the above diode values are not equal, the IO can generally be judged bad.
Oscilloscope measurement logic is best