Hi everyone,

I have a Samsung SP0802N that won't spin up (no noises). When the drive was removed from the computer there was a diode (TVS diode?) right by the 5V power connector pin that was hanging off the board. It seems it was heated to the point where one end of the diode desoldered itself from the board.

Here is what I think may have happened...
Bad power supply was feeding the drive too much power so the Diode kicked in to route that power away from the HDD, that extra power heated up the diode to the point where it was so hot that it desoldered itself from the PCB board. So the overpower protection for the HDD was disabled at that point, and it fried something on the HDD.

I am trying to determine if a board swap would be a way of recovering data off this drive. When I apply power to the HDD the large chip and rectangular Samsung chip on the PCB heat up (not really hot just warm). Also when I slowly spin the drive in my hand I can hear what sounds like the platter spinning (no stuck head, or seized motor?).

So what do you guys think? Is there anything else I should try, or do you think there is something wrong with the spindle possibly?

I have swapped PCB boards and ROM chips on a number of HDDs with great success, although I don't see a ROM chip on this board.

I have included some pictures for reference.

Anyways thanks for your time!

Here is a picture of a similar board with the diode still on it.
From my limited knowledge the components to the left of the diode are capacitors, but I could be wrong.
The diode removed itself essentially.

The 5V TVS diode does not have a fuse. There is a zero-ohm resistor near the screw, but that's for the 12V TVS diode ("LEM") near the other screw.

Since the 5V TVS diode desoldered itself, this would suggest that the overvoltage persisted for a significant time, in which case the preamp may have sustained damage.

I'm not a data recovery professional, but your board may be one of these where a straight swap might work.

If you would like to measure some voltages, I could help you with that, but it may just turn out to be a post mortem exercise.

_________________
A backup a day keeps DR away.

Yes I read that before posting, I wonder if his PCB swap worked out?

So if the preamp was damaged then it would be a clean room job would it not, and not fixable with a PCB swap?

If you would help me measure some voltages that would be great, thanks a lot.

Here is my analysis of a similar board:

Tutorial - how to locate the basic test points of an unfamiliar HDD PCB:
http://www.users.on.net/~fzabkar/HDD/Tu ... 0411N.html

In your case you would need to measure the voltages at the pins in the highlighted boxes of the attachments. Be very careful, as a slip of the probes will cause major damage. Remove the board from the drive when testing it.

_________________
A backup a day keeps DR away.

Here are the voltages.

Thanks again for your help!

The +1.2V Vcore and +2.5V Vio supplies for the MCU are OK. This would suggest that the MCU probably survived the overvoltage.

The +3.3V supply for the SDRAM is generated by a small portion of the analogue section of the HA13627 motor controller. It's OK, too.

However, the -5V supply for the preamp is missing (0V and 0.09V). This supply is generated by the motor controller IC. Some HDD models can switch off this supply, but others will switch it on, regardless of whether the board is attached to the drive. The SP0411N in my tutorial switches it on. Therefore I suspect that your board's motor controller may be dead. This chip is directly powered from the +5V rail.

I would install the board on the drive, select the 200 ohms range on your multimeter, and measure the resistance between the "0" and "0.09" test points in the second photo clip. This will test whether the preamp has a short on this rail. Also measure the same resistance on the PCB with it disconnected from the drive.

_________________
A backup a day keeps DR away.

With the PCB disconnected there is no measurement (infinite). With it connected it measures 3.3.

If you mean 3.3 ohms, then the preamp is dead.

_________________
A backup a day keeps DR away.

LOL, so the preamp is shorted then? Well at least I can have some closure now
and saved some money on a PCB board that wouldn't have solved the issue.
Do you have any way I can make a donation as thanks for your help?
Thanks!

Save your money for a new HDD.

_________________
A backup a day keeps DR away.

Hi Fzabkar, Forumers

If the preamp is dead, why should the Spindle not rotate ? One, at least me, expect the Spindle to rotate but the head, well it can click or be dead. Is it because the MCU POS test detects the Preamp failure and disable the Spindle motors and other parts. I just want to know the startup procedure the MCU does before the Drive starts to work.

Thanks