Another SD-connect problem with 1394 signals

Hi,

As you probably remember, last year, I sent back the SD-connect in warranty for an issue related to audio.
After a month you sent back the converter repaired (even if I found it with a corner dent on the back panel and with the fornt panel power switch broken) Anyway was perfectly functioning.
Now, after one year, the unit presents a new problem:
the firewire interface seems died.
In DV mode, the computer does not recognize the unit, either in playback mode and in capture mode.
Also connecting it to a DV videocassette recorder, the problem is the same: the VTR says that there is no incoming DV signal.

In the stand-alone mode (uncompressed), the unit seems to work fine.

What can be happened? Could it be a failure on the DV circuitry? And why?
It is the second time that this converter presents serious problems and I'm really unsatisfied about it.

What can I do?
Another return?
But now the converter is no more in warranty, how much I have to pay for repairing it? (since I live in Italy, only shipping cost are about 150 USD).

Please let me know as soon as possible.