Got an electric shock from a USB type C cable plugged to a laptop, how can I find the faulty thing?
IF the shock was mild the most probable cause is that the power supply is intended to have an earth connection (3rd pin) but does not have one, and has two &quot;Y&quot; filter capacitors on it's input side from each AC input line to its input ground lead. This causes the disconnected ground to float at Vinput_AC/2 at an impedance of about Zcap/2. If the input ground is connected to Vout_negative (as happens) then the voltage is enough to cause an unpleasant sensation to a grounded user who touches it.
Measuring from Vout_negative to mains ground should return a voltage of V_mains/2 or less (as the meter MAY slightly load the voltage.
The &quot;solution&quot; is to ground the ground lead on the power supply or the Vout_negative connection. Worst case this may cause operational issues, but shouldn't.
Worst case operationally is that

connecting this power supply to equipment, OR

connecting equipment connected to this power supply to other equipment,


MAY cause damage or destruction of some of the equipment.
Ask me how I know :-(. (Long ago).