| Problem | Solution | |--------|----------| | | Disable driver signature enforcement (see Step 3) | | COM port appears then disappears | Bad USB cable or power supply (JK 721 needs 12V 2A+) | | Cuts are mirrored or scaled wrong | In software, disable “Mirror” and set correct media width | | Plotter moves but doesn’t cut | Check blade depth & force settings (software override) | | Windows 10 update breaks driver | Reinstall CH341SER or roll back USB driver in Device Manager |
Ensure the baud rate and flow control in your software match the plotter's hardware settings (often found on its LCD panel). 4. Pro-Tip: The "Old School" Reliability Jk 721 Cutting Plotter Driver Windows 10