SMax77

Hi, all. I've faced a problem with my 7200.12, looks like a "0 LBA" shown here. After power up it sounds "t-r-r-r-r" 4-5 times and stops. But the main problem is that I can not receive any answer from hdd to terminal 0x1A command (hex Ctrl+z command, isn't it? I'm using very simple "Terminal" with hexadecimal transmitted codes). RS232 - TTL adapter connected correctly (sure by a huge number of forums and oscilloscope - I'm electronic engineer). My hdd do not respond me in any condition of PCB and the brick: Fully connected - failed, Motor disconnected (by isolator) - failed, heads disconnected (by isolator) - failed. hdd "no reply" state is confirmed with oscilloscope (no changes on sygnal). port settings : 38400, 8 data, 1 stop, no parity, no handshaking. hdd: SN: 6VPEDKLG model:ST31000524AS firmware: JC4B PCB 100574451 rev.B Could anybody help me? May be I need to short something? disconnect something? Send other command? Thanks a lot in advance.