HP 3840 - Manual (Page 81)

If you receive this error message, ensure the USB cable is not greater than five
meters (approximately 16 feet, 5 inches) in length. Connect the printer directly to
the USB port on the computer and not to a USB hub.
An error message appears while the Power light is flashing
Read the error message explaining the problem and its solution.
For more information, see
Power light is flashing .
11.11 If you continue to have problems
If you continue to have problems after investigating the troubleshooting topics, turn
off your computer and then restart it.
If you still have problems after restarting your computer, go to HP customer support
at www.hp.com/support .
HP Deskjet 3840 series printer User's Guide
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