Can't connect to Melzi, but uploading firmware works fine!

Hello RepRapers,

I can't connect to my Melzi board via USB any more. It has worked flawlessly before with Pronterface, Repetier Host and Simplify3D.

However, I can upload new firmware to the Melzi board from Arduino Win software without problems.

No LED on the board is flashing.

Someone who can help me find out where the problem is?

(Printer is a Mendel90)

Thanks,

Martin from
Sweden

You checked that the baudrate corresponds to the one coded in the firmware?

Yes, no luck. I have tried with many different baud rates as well.

I have also:
*Tried another USB cable
*Reinstalled the FTDI drivers
*Re-soldered the FTDI chip, USB connector and some other components on the Melzi.
*Tried with another PC.

But if some component on the Melzi that deals with the communication is fried, I shouldn't be able to upload firmware?

The printer works fine except for this problem.

/Martin