Maybe you should check if the TX- and RX-wires to your RS232 <=> TTL interface are properly making contact (and be sure the ground is also connected). If that doesn't work... well, maybe your PCB indeed is fried, who knows? Greetz, Peter. After test the hyperterminal connection with the PCB removed from the HD, I tried to remove the "BUSY" problem following the how-to. All seemed good during the process but when I restarted the disk, it doesn't respond to any command in hyperterminal. Now the disk is detected by BIOS, but not by Windows and it doesn't respond to the inputs I've tried in the hyperterminal. Thanks