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Repair a hard disk

Last response: in Storage
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August 30, 2012 3:01:36 PM

Hello,
I have got an Fujitsu 100GB 2.5" IDE hard drive. Model Number: MHT2100AT. The hard drive 5 volts got connected to 12 Volts and an IC on the PCB has Blown. Does anyone know what the IC is and can I replace it?

More about : repair hard disk

a b G Storage
August 30, 2012 3:07:58 PM

integrated circuit.

if you buy a matching hard drive, it is possible for a person to change the little circuit board on the bottom of the drive.
a c 300 G Storage
August 30, 2012 8:20:37 PM

Is it an IC or a TVS diode? If it's a TVS diode, then it is probably shorted, and there will probably be a 2 amp fuse which has gone open. Assuming there is no other damage, then the solution is to remove the diode and bridge the fuse with a blob of solder or a wire link.

See http://www.users.on.net/~fzabkar/HDD/TVS_diode_FAQ.html

Does your board look anything like these?
http://www.users.on.net/~fzabkar/HDD/MHW2080BH_fuse.jpg
http://www.users.on.net/~fzabkar/HDD/MHV2100AT_fuse.jpg

Can you upload a detailed photo?

BTW, it appears that your drive's PCB can be swapped directly, ie no chip transfer is required:
http://www.donordrives.com/hard-drive-pcb-donor-swap-ma...
http://www.donordrives.com/blog/pcbswapguide
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September 2, 2012 3:28:05 PM

Hi Thanks for the info.
I have check the fuse and it is ok. It looks like the IC near the coil has blown?
Does anyone know what it is and how I can get a replacement?
The IC is an 8 pin IC with the markings D91 02 P0 I think it is a step down voltage regulator?

I have taken a picture but do not know how to upload it on the forum - can anyone help?

Any help will be great

a c 300 G Storage
September 2, 2012 8:12:20 PM

You can upload your images to a file sharing site. If possible, could you provide a direct link to the JPG file, without ads, banners, popups, etc?

As for the IC, without seeing the circuit, I would think that it is either a PWM controller in a switchmode regulator, or a MOSFET chopper. In recent designs, the PWM controller is inside the motor controller IC, so I'm tending toward the MOSFET. If there is no Schottky diode nearby, then the IC may incorporate both the MOSFET and the diode, which would make it a "FETKY". With Fujitsu being a Japanese manufacturer, I suspect that the IC is probably also a Japanese part, maybe by Hitachi/Renesas, Sanyo, Rohm, NEC.

Edit: Could it be this part?

BD9102FVM, 4.0V(or 4.5V) to 5.5V, 0.8A 1ch Synchronous Buck Converter Integrated FET:
http://rohmfs.rohm.com/en/products/databook/datasheet/i...
September 3, 2012 12:24:41 PM

fzabkar said:
You can upload your images to a file sharing site. If possible, could you provide a direct link to the JPG file, without ads, banners, popups, etc?

As for the IC, without seeing the circuit, I would think that it is either a PWM controller in a switchmode regulator, or a MOSFET chopper. In recent designs, the PWM controller is inside the motor controller IC, so I'm tending toward the MOSFET. If there is no Schottky diode nearby, then the IC may incorporate both the MOSFET and the diode, which would make it a "FETKY". With Fujitsu being a Japanese manufacturer, I suspect that the IC is probably also a Japanese part, maybe by Hitachi/Renesas, Sanyo, Rohm, NEC.

Edit: Could it be this part?

BD9102FVM, 4.0V(or 4.5V) to 5.5V, 0.8A 1ch Synchronous Buck Converter Integrated FET:
http://rohmfs.rohm.com/en/products/databook/datasheet/i...


Hi thanks for the info
I have taken an image of the PCB and put it in dropbox
http://dl.dropbox.com/u/92701335/DSC03618.JPG

I think the IC is the same as the one you are talking about.
Where can I get this IC from?

regards
a c 300 G Storage
September 3, 2012 9:54:30 PM

I'm finding it hard to see any damage to the IC, but before looking for a replacement, I would measure the resistance between the 4R7 coil and ground. If you find a short, then the Marvell MCU would have to be suspect. The IC is a fixed 1.24V regulator that supplies the MCU's Vcore. I would also measure the resistance between the IC's Vcc and SW pins (8 & 6). A typical failure in a switchmode supply is a shorted chopper transistor, in which case the load would see the full 5V supply rather than 1.24V.

Elsewhere on the PCB, probably at about 5 o'clock to the TI TLS2291A motor controller, would be a 3.3V regular, probably a linear type. A suitable test point would be pin #8 of the 8-pin ST serial flash memory, or pin #1 of the SDRAM.

As for where to buy a replacement IC ...

http://www.digikey.com/product-detail/en/BD9102FVM-TR/B...
!