dear friend & seniors
I have a hard disk
seagate BARRACUDA ATA
Model ST320011A
i have replace a damaged pcb with ok pcb but hard disk has no power
please guide me how i solve this problem

IF PCB is compatible, either headstack is killed (you have a precise output) or motor is killed, or both.

Time for cleanroom work

Doesn't work

I mean that



won't work

Dear Spildit
yes drive spin up
what is (pre-amp is shorted)?

If you remove contacts from heads you should get an error in terminal and motor SHOULD NOT spin up .

So either the problem is elsewhere or something is missing from the diagnose.

Anyway if something at HS is badly shorted it will prevent EVERYTHING from starting and can kill a new PCB also.

The damaged chip is the motor controller, and the damage is on the motor side. Did you measure the resistances between the motor terminals?

You could also verify the voltages at the LX8815-33 regulator and the FDFS2P102A FETKY. See the attachment.

FDFS2P102A, Integrated P-Channel PowerTrench® MOSFET and Schottky Diode, Fairchild, 20V, 3.3A:
http://smartdata.usbid.com/datasheets/u ... 2p102a.pdf

LX8815-33, 3.3V, Linfinity, Dual Channel 1A Low Dropout Regulator:
http://www.datasheetcatalog.org/datashe ... SC1645.pdf

_________________
A backup a day keeps DR away.

AIUI, what he's saying is that this is one of those drives where the MCU needs to be able to see the preamp before it even tries to spin up the drive.

Preamps have a serial interface by which they communicate with the MCU. You can see it in the following block diagrams:

http://malthus.zapto.org/viewtopic.php?f=59&t=229&p=582

_________________
A backup a day keeps DR away.