How to diagnose USB power errors using Micromat's USBee tester

Learn how Micromat's USBee Circuit Tester assists Mac, iPhone, iPad, and other USB peripheral users in confirming when USB electrical problems are to blame for malfunctions.

Image: Micromat

Occasionally anomalies arise when connecting and operating USB peripherals. External hard drives, smartphones, flash drives, printers, tablet computers, digital cameras, and security cameras are among the USB-connected devices Mac users regularly operate but that can experience electrical issues. The first temptation is frequently to assume a software configuration or communication error is to blame, but sometimes electrical problems prove to be the culprit.

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Micromat's USBee Circuit Tester enables determining when USB ports or connected peripheral problems are occurring due to power-related issues. The diagnostic device--a small white plastic box with a standard USB cable, digital readout, one button, a USB Type A port, and a micro-USB port--also can confirm whether common smartphone, tablet computer, and e-reader charging blocks are working properly.

The $29.99 USBee USB Circuit Tester plugs in line with USB devices connected to a Mac or a Windows system. The tester's digital readout displays the voltage the Mac or Windows system's USB port generates, typically 4.7 to 5.3 volts.

The output test also confirms whether the charging blocks mentioned earlier are functioning properly. The diagnostic information helps determine whether a digital device isn't charging properly due to a bad charger or a bad cable. On a few occasions I've encountered what I thought was a failed charging cable, only to figure out later the charging block was to blame. The USBee tester eliminates such confusion: If the charging block is passing 4 to 5 volts, it's likely the cable is to blame, whereas if the charging block isn't generating the proper electrical current, the cable may be fine, and the block probably needs replacing.


The USBee Circuit Tester simplifies diagnosing failed charging blocks, failing logic boards, and malfunctioning USB peripherals.


Because the USBee possesses both USB Type A and micro-USB ports, you can test USB peripherals to determine whether they are working properly electrically. When the USBee is connected to a Mac or a Windows machine, and a USB peripheral is connected to the USB diagnostic tool's Type A USB or micro-USB port, the device begins displaying amperage and tracks milliamp hours for the connected peripheral.

When the USBee detects voltage outside the 4.7 and 5.3 volt range, the screen flashes and an up or down arrow will appear to alert the tester that electrical values are falling, respective to the arrow, outside the typical range. Testing data can also be saved to memory by double-pressing the device's lone button. Memory slots are cleared by double-pressing the button and then holding the button for three seconds.

While it's unlikely that iPhone, iPad, and Mac users will often find connected peripherals experiencing power anomalies, the USBee can help detect a failing logic board, which is more common.

The device's greatest advantage is its ability to confirm whether charging blocks are operating properly. That feature alone, combined with the simplicity of operation--just connect the tester to a charging block and view the display--justifies the device's expense.

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