Arduino Trouble Shooting

ZYLtech boards are double- and triple-checked for quality and functionality. Occasionally, however, our boards do not work properly and the following steps typically solve 60% of the problems our customers encounter. Please consider walking through these steps prior to requesting a return. We are happy to assist you - feel free to contact us for help.

1. Visually check the board - is there any physical damage or bad solder joints? Note that the capacitor is particularly susceptible to damage. If the headers are bent they can be straightened by hand or with pliers.

2. Approximately 30% of the reported malfunctions are due to an unstable connection. Consider trying another USB cable and/or connecting to a different USB port on your computer. (Occasionally the front panel USB ports lack the current required for the boards.)

3. The LEDs are helpful diagnostic indicators whether you have an UNO, Mega, or Due, and whether you have the Atmega16U2 or CH340 version. Regardless of the version, there should be a least two LEDs that light up on the board. One of the LEDs should blink, which indicates the factory loaded firmware is working; the other LED should be steadily on.

4. Even if the factory loaded blink sketch is working, driver problems can prevent you from connecting the board and uploading your sketches. Though the CH340 driver should be installed automatically on most operating systems when the board is plugged into the computer, it is possible that your antivirus or firewall software will prevent a complete installation (or prohibit the installation altogether.)

5. If the issue is indeed a CH340 driver problem, you may download the Windows version of the driver HERE. To install the driver, you must be signed in as an administrator. Run the SETUP.EXE file in the CH341SER folder or follow the steps below to install it manually. PLEASE MAKE SURE YOUR ANTIVIRUS/FIREWALL SOFTWARE IS DISABLED.

  • Swipe in from the right edge of the screen, and then tap Search. (If you’re using a mouse, point to the lower-right corner of the screen, move the mouse pointer up, and then click Search.)
  • Enter Device Manager in the search box, and tap or click Device Manager.
  • In the list of hardware categories, double-tap or double-click the category your device is in and then double-tap or double-click the device you want. For example, to see your video card, tap or click Display adapters, and then double-tap or double-click the video card name.
  • Tap or click the Driver tab, tap or click Update Driver, and then follow the instructions. You might be asked for an admin password or to confirm your choice.


Note: If driver is installed correctly, you should be able to find USB-Serial CH340 device in the Device Manager. The COM port is the one you are going to use in the Arduino IDE.

Get the latest updates on new products and upcoming sales