Hi,
I tried to find some specification on the Internet, too - nothing...
There is one Fet for each disk and 5V and 12V Power supply.
. 
On my board I made a simple test and connected a resistor instead of the disk.
Then I measured how much the voltage drops at the transistor.
	
		
			
				|   | Kaynak kod | 
			
				| 1
2
3
4
5
6
 | Voltage       = 12.05 V
Load resistor = 11 Ohm
--> Current   = 1.1 A
Voltage Drop  = 40 mV
Result R=U/I  = 36.5 mOhm | 
		
	 
 
So this part [attach]261[/attach] is a P-Channel Mosfet with a typical Rdson of about 40mOhm
Any P-Ch Mosfet with this package (SOT23-6), a similar Rdson, max. Vds and Vgs of 20V or more could be used.
A part matching would be the Toshiba TPC6108
For a temporary repair you could remove the blown one and connect the two 12V (yellow) wires of the hdd power cables.
Or you short the S-D solder pads.
Regards,
HWguru