HItachi HDS721050CLA362 LOGIC BOARD SHORTED

[deb95]

I accidentally shorted my PC HARD DISK. It accidentally touched a metal surface and burned a capacitor on the logic board.
It is not spinning and also not detecting.
Is it possible to fix the board by replacing the burn capacitor?
I checked the board for any short circuit near the OA56511 IC ( may be a voltage regulator) and the only thing shorted is that the burned capacitor.
It will be very helpful if someone can provide any information and guidance on troubleshooting and fixing the logic board.

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[fzabkar]

See http://www.hddoracle.com/viewtopic.php?f=59&t=231&p=596#p9159

The OA56511 IC is a spindle motor +VCM + power controller.

If you remove the capacitor, does the short circuit persist?

[shahij]

Better you buy a new board, let me know if u need 1.

[deb95]

See http://www.hddoracle.com/viewtopic.php?f=59&t=231&p=596#p9159

The OA56511 IC is a spindle motor +VCM + power controller.

If you remove the capacitor, does the short circuit persist?

I have not removed the capacitor yet, but it burned on of its solder pads and it is completely isolated from the circuit except the ground connection.

[deb95]

I removed the capacitor from PCB and one of the pads are completely burned. I checked the cap and it was shorted, now there is no short in the PCB.
The only thing is that the capacitor(no specification)?

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[fzabkar]

@deb95, it would help to determine the function of the shorted capacitor.

To this end I would test the capacitor pads for continuity with ground, +5V and +12V (SATA power), and the Vcc pins of the SDRAM (pin #1) and serial flash memory (25FU206, pin #8).

If there no connection to any of these supply voltages, then the capacitor may the boost capacitor for the VCM circuit.

[deb95]

@fzabkar
+5V and GND are directly connected to the capacitor.
There are two other pins from the OA56511(do you have any datasheet?), that are directly connected. (see the pictures)
No connection with the flash memory(25FU206) and SDRAM(K4H281638L, Samsung).

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[fzabkar]

It would appear that the capacitor filters the +5V supply to the motor controller. Those two pins would be the Vcc and ground for the IC. On that basis ISTM that you could make do with a 10uF MLCC or even a low ESR leaded electrolytic capacitor. Just make sure that the chip's pins make contact with the thruholes. In fact, if the traces are still intact, then the PCB may work without any capacitor at all (although you should still replace it).

Best of luck.

I don't have a datasheet, BTW. I believe that these motor controller ICs are custom designs.

[deb95]

@fzabkar
It worked, and a lot of thanks for your support.