Don't risk it, Check it...

What is it?

USBcheck is a testing device that enables you to test  the power wiring on USB ports. It indicates if there is power, if the polarity is correct and helps detect intermittent power problems on the contacts or connections.



In order to understand this part, we will explain a little about "external" USB ports. External USB ports are those ports that exist on the front, side or rear of your computer case and are connected to the motherboard via a cable. Each port requires 4 or 5 wires connected to a header connector on the motherboard as shown below:

Pin Function  
1  5 Volt
 Data (-)
 Data (+)
 Shield (if available)

Each wire must be connected to the corresponding pin on the header. (This information is provided in the motherboard´s manual).

 2 x 4 Pin Connector    Single Wire Connector
INTEL standard USB header on Motherboard
Each header supports 2 USB Ports


The problem is that many PC cases and motherboards do not have a "keyed" connector  to prevent wiring it incorrectly. It is very easy to make a mistake, especially when the header is located in a hard to reach area.

The worst case is when the +5V wire is swapped with the Ground wire (common with the 4 Pin connector).

In this situation, if you connect a USB device to the corresponding USB port, most likely will result in permanent damage to the device or even your motherboard, depending on the type of device you plugged in.

Here are some examples with Reverse Polarity:
You connect a small device (powered from the USB port) like a Flash drive, external Drive 2.5" or Webcam, the device will get damaged and you loose all your files in case of a Flash Drive or External Drive 2.5".
Since you don´t know exactly what happen, (likely) you will get another USB device to try [human nature] and guess what? You just caused more damage!!!
(Read this story on Tom's Hardware)
If the device receives power from and external source like a Digital Camera, Camcorder, Scanner External Drive 3.5" or Printer the damage could happen on the device or the motherboard, since the device could feed power to the motherboard.
In some computer cases you don't need to plug in any device to cause damage. If one of the 4 pin connectors is connected correctly and another incorrectly, it may cause damage to the motherboard if the USB ports on the case have a shared ground, creating a short between 5V and Ground:
Click image to view full size

All the ports that are connected via a cable to a header on the motherboard. These are generally found in the front, side or rear of Desktop cases, as shown below:
Front USB Ports
Side USB Ports
Rear USB Ports


How do I know if my USB ports are wired correctly?

This is where the USBcheck tester comes in. In the past to test  the USB ports you would have to open the case and physically verify the connections or plug-in a USB device (Flash/Pen drive, External Hard Drive, MP3 player, etc) and risk damaging it. Not anymore... you can now use USBcheck tester.


Do I need to install drivers or software?

No. All you need is to turn on the computer. It will work even if some components are not installed - Hard Drive, CD/DVD drives, Graphic Cards, etc. It only needs the motherboard to power-up.



Yes. It will work with USB Version 3.0 - it won't be obsolete e a few months.


Does it work with different operating systems (Windows, Linux, Mac, etc) ?

Yes, it does not depend on the operating system.



No, after you test the port with the USBcheck tester, you need to plug-in a USB device (follow the manufacturer's instructions) or use other test equipment designed for that purpose.



Easy. With the computer turned on:

  • Plug the USBcheck tester in a USB port. Look at the light emitted:
    • GREEN Light - Power OK
    • RED Light - Warning  POLARITY REVERSED (Do not use until problem corrected)
    • Both Lights OFF - NO Power or Short between 5V and Ground (verify the wiring and Motherboard connections)
Test for BAD power connections (Connect the USBcheck tester to the USB port to test):
  • If the GREEN light flickers ON/OFF:
    • While you GENTLY wiggle the USBcheck tester from side to side and up/down motion - Bad connection on the contacts or solder joints on the USB connector.
    • While you wiggle the cables connecting to the USB Port - Bad cable of bad connection at the header on the Motherboard.
This test is very useful for Laptop / Netbook Computers
or other equipment where the USB port is soldered to the main board

IT Professionals  & Technicians:
  • When building new systems test the USB ports power/polarity before plugging in any other USB device, as part of your quality control.

  • If you use USB Flash drives (Pen), External USB Hard Drives or other USB devices when repairing PC's, test the USB port before connecting your devices.

IT Students:

  • Learning how to repair or assemble PC's ? This tool is ideal for inexperienced technicians as it provides that first test before you plug-in a USB device and risk causing damage.

Computer Business:

  • Sell it to your customers when they purchase USB equipment. This may reduce your merchandise returns due to connecting the equipment to PC's with incorrect USB wiring.

  • Supply one to every technician in your service department. If you build PC's, incorporate this test as part of your quality control. This will allow the technicians to test the USB ports of computers coming in for repair thus reducing the chance of damaging the USB devices used in your shop.

Computer Users:
  •  Test the USB ports of your newly purchased or repaired desktop PC.
  • If you like to build your own systems but have trouble connecting the USB cables to the motherboard header.

  • If you use your USB devices in Internet Café's, Libraries, Schools or someone else's computer always test the USB port with the USBcheck if you want to be sure.
Other equipment with USB Ports
(Vehicles, Medical, Multimedia, Test Equipment and much more)

  • USBcheck provides a fast and quick way to verify the power lines on the USB ports avoiding hours of troubleshooting and the frustration that comes with it !
  • It can be used at many levels: Manufacturing, Assembly, QC Testing, Repair, Troubleshooting, etc...

check offers you peace of mind, when it comes to using USB devices...

Useful Links
Learn more about USB ports & Power Problems in USB ports:

  • Tom's Hardware
    (Posted by a user) "I do the whole 'human nature' thing and plug in my only two external USB hard drives, the second containing literally EVERYTHING. 13 years of work basically, completely irreplaceable data. "

  • Tom's Hardware
    (Posted by a user) "USB port FRIED 5 devices"

  • Directron

  • HowStuffWorks
  • USBman (no longer online)   "Improperly wiring a USB port can result in permanent and fatal damage to the motherboard, the USB port and ANY peripheral connected to the motherboard."
    (This site no longer exists - The link goes to an archive)

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