1. Determine that there is a signal cable unplugged all the cables, at this time the test passes means that the cable has a problem, you need to add *** mode inductance to solve the problem of the cable's current, and then all the cables and equipment coupled, the test passes.
2. Unplug all the cables to measure the exceedance or only the power cable, then you need to add a magnetic ring on the power line, there is an improvement, to deal with the **** mode current in the circuit, and then again, there are two cases of testing, qualified or unqualified, and if it is the latter you need to check the chassis shielding.
3. No cable (such as battery-powered devices), directly check the chassis shielding.
It should be noted that the rectification should be done when the EMC rectification planning.