Warning about chinese Melzi Boards (with solutions)
A little or BIG warning to all owners of those chinese Prusa i3 clones with MELZI boards:
ALL of the shipped melzi boards from china are using a FAKE FTDI chip (this is the chip for the serial to USB communication).
There was a problem (I think about 1-2 years) where windows did update automaticially the drivers with a "special" one from FTDI. Result: The "fake" FTDI were bricked from software side (there was an time intensive option the reanimate them)
But NOW: FTDI and windows update did it again! Not the hard way, but if your printer stops from working and you cannot connect to the printer, use any serial terminal, take the right port and look at the output: It will scrolls continously "Fake FTDI chip detected!"
Solution #1: Revert the FTDI driver manually. Google for it. And keep an eye of the windows updater in future.
Solution #2: Buy a cheap HC-06 bluetooth dongle (there are many manuals how to implement it on melzi board) and use only bluetooth for serial communication
Solution #3: Buy a RAMPS 1.4 and a mega2560 (So did I)
Final Solution: Never buy a FTDI product anymore, no even an original one.(but this should be another discussion)