Using qualMeter for Testing USB Ports



Some of my PC USB devices keep getting intermittently disconnect so i though i use my qualMeter X to test and i found the difference in current quite significant between different USB ports in my motherboard.

My question is how accurate is the output of the qualMeter X? If the output drops to worst does that mean my USB port is failing?


The qualMeter only tests the power output, not the data… though if the power output is insufficient (bad fuse, etc) then it can cause random disconnects when the device tries to draw more power than the port’s capable of putting out.

I know many USB ports use what’s called a resettable fuse on their power lines which, once tripped, may not return to their original values and thus may cause a higher-than-normal voltage drop.



@Doktor_Jones has the point.

The insufficient power supply on the port could cause intermit-tenting. Normally, unless the USB ports on your motherboard are different types (USB2.0/USB3.0), they should share the same power supply from the motherboard. General speaking, normal USB2.0 port should have less then 1A output, and USB 3.0 should be less then 2.0A. Therefore, you should get quite even results when you test their output.

BTW, with qualMeter X, the charger test is not telling you Best to Worst. It tells you exactly the output in 100mA per step from 1A~3.1A. Unless the ports output is less then 1A, the red LED will flash.