My HITACHI is dead...

The defective component should only be a protective device as it is connected between +5V and GND. It gave his live trying to save the sensitive electronics in vain.

An undamaged drive should work even with this component removed. Something else seems to be wrong. Perhaps it's just a step down switching voltage regulator, but it might also be the complete electronics. I don't think the schematics are available and I think there is a only a small chance that someone skilled with electronics repair might be able to repair it.

Thank you very much, Soleil!
I thought it was Diode. I`ll try to find a replacement for this part.

Perhaps it's a SM6T6V8A (unidirectional) or SM6T6V8CA (or bidirectional) which was destroyed by overvoltage (12V?) or reverse polarity (in cas of unidirectional SM6T6V8A). But I fear replacing this device won't change the situation.

Here`s what I found:
http://www.techsupportforum.com/hardware-support/hard-d...

I`ve replaced the diode & it`s working!!! Its absolutely new!!!