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Old 07-07-2009, 02:55 AM   #1
BigAlNZ
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Post Removing ROM IC's on HDD PCB

What would you guys reccomend to remove ROM IC's on HDD PCB's (both 25 and 2.5 ones).

I havent got loads of money so was looking at a Steinel hot air gun, but as always I value the opinion of people on here.

-Al
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Old 07-07-2009, 08:27 AM   #2
Wizard
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Default Re: Removing ROM IC's on HDD PCB

There are none. It's embedded into the BIG IC where interface straight into there.
Been this way for 12 to 15 years now. And also last 5-6 years much of makers now put the firmware in very well protected spot on the platter instead of a 2 dollars IC and does work well.

Cheers, Wizard
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Old 07-08-2009, 04:39 AM   #3
BigAlNZ
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Default Re: Removing ROM IC's on HDD PCB

Quote:
Originally Posted by Wizard
There are none. It's embedded into the BIG IC where interface straight into there.
Been this way for 12 to 15 years now. And also last 5-6 years much of makers now put the firmware in very well protected spot on the platter instead of a 2 dollars IC and does work well.

Cheers, Wizard
Not quite true. There is still a flash chip on the PCB. Have a read of this excellent article:

http://hddscan.com/doc/HDD_from_inside.html

See where he has circled the chip "flash" and then further down:

"Flash chip stores part of the drive's firmware. When you apply power on a drive, MCU chip reads content of the flash chip into the memory and starts the code. Without such code drive wouldn't even spin up. Sometimes there is no flash chip on PCB that means content of the flash located inside MCU"

This article refers to a modern 1Tb drive, so while yes some parts of the ROM are on the SA of the disk, most disks still have a flash chip on the PCB.

Cheers

-Al
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Old 07-08-2009, 08:51 AM   #4
Wizard
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Default Re: Removing ROM IC's on HDD PCB

Al,

Have this particular PCB? Can you read this markings on this IC for us so we can be certain to tell you what it is?

Like I have said, almost all HD makers have done away with EEPROM IC, either is embedded in big microcontroller or written to the platter in well-protected area that even low level format (still not recommended!) can not touch that.

Only time might find that on SCSI/ Serial SCSI drives.

Cheers, Wizard
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Old 07-08-2009, 04:26 PM   #5
i4004
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Default Re: Removing ROM IC's on HDD PCB

wizard is right.
i'm highly sceptical about such attempts to fix hdd.
it can easilly happen that you swap COMPLETE pcb(not just one chip, whoch usually is not existant, as wizard says..heh) and gain nothing, because most of the time it's the stuff on platters that gets corrupted....

as for your question, sure try it: just heat one side(with decent size soldering iron) and lift it slowly so that pins are no longer touching pcb...then heat other side and it's off....as it's such a small chip...
you don'0t need special tools for such a small chip.

aldo search youtube for "smd desoldering" etc.
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Old 07-08-2009, 05:12 PM   #6
BigAlNZ
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Default Re: Removing ROM IC's on HDD PCB

Quote:
Originally Posted by i4004
wizard is right.
i'm highly sceptical about such attempts to fix hdd.
it can easilly happen that you swap COMPLETE pcb(not just one chip, whoch usually is not existant, as wizard says..heh) and gain nothing, because most of the time it's the stuff on platters that gets corrupted....

as for your question, sure try it: just heat one side(with decent size soldering iron) and lift it slowly so that pins are no longer touching pcb...then heat other side and it's off....as it's such a small chip...
you don'0t need special tools for such a small chip.

aldo search youtube for "smd desoldering" etc.
I am not advocating a ROM swap on its own. What needs to be done in the case of PCB errors on HDD is normally to swap the PCB for a very close match AND swap the ROM chip on the PCB.

I have got a bunch of Seagate drives here all with ATMEL ROMS (one in particular I am looking at right now is a ATMEL428)

Did you read the article I posted a link to? It clearly states that the ROM is split between the SA of the drive and the ROM chip on the PCB (majority admitadly on SA of drive)

See here are well : http://forum.hddguru.com/diy-what-th...al-t12671.html

And here : http://forum.hddguru.com/newbie-info...etc-t6562.html

I dont claim to be an expert, but everything I have read suggests that if yuo are doing a PCB swap you need to swap the ROM chip too.

HTH

-Al
PS: I aint that handy with a soldering Iron, I tried with two 2.5" drives and screwed the PCB! Lol!
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Old 07-08-2009, 07:18 PM   #7
Wizard
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Default Re: Removing ROM IC's on HDD PCB

Problem is this EEPROM have too many traces going to this IC. A serial EEPROM always have 3 wires. clock, data and voltage. The other 5 pins are grounded usually.

For Amtel ICs, it is always two letters (AT) followed by two digits for product group then other characters for type of item.

So to speak, it is not valid number. If yo can find more characters on this IC?

Cheers, Wizard
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Old 07-08-2009, 07:36 PM   #8
BigAlNZ
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Default Re: Removing ROM IC's on HDD PCB

Quote:
Originally Posted by Wizard
Problem is this EEPROM have too many traces going to this IC. A serial EEPROM always have 3 wires. clock, data and voltage. The other 5 pins are grounded usually.

For Amtel ICs, it is always two letters (AT) followed by two digits for product group then other characters for type of item.

So to speak, it is not valid number. If yo can find more characters on this IC?

Cheers, Wizard
Will check when I get home. To do one whole side of the IC I need to get a fatter tip...
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Old 07-09-2009, 03:49 AM   #9
BigAlNZ
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Default Re: Removing ROM IC's on HDD PCB

Quote:
Originally Posted by BigAlNZ
Will check when I get home. To do one whole side of the IC I need to get a fatter tip...
25F512N ?
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Old 07-09-2009, 08:41 AM   #10
Wizard
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Default Re: Removing ROM IC's on HDD PCB

Always put in full part number and description of the IC type. Certain this is on your hard drive? Especially consumer hard drives hard to say for sure.

AT25F512N is serial eeprom 8 pin IC but there is other one that is:
AT49BV512 that uses 32 pin SOJ IC (usually found on mainboards).
Both are Amtel

But there is another IC with same looking numbers:
AMTEL228 AT25F512N which is BGA IC only done with hot air soldering and no way to socket it to extract data or program it. The socket is very $$$ and specially made, usually used for testing prototype and production BGA ICs before committing to PCB board.

Might be you mistaken 8 for B?

I'll wait till you confirm again for certain. And a digital pictural of marco close up of said IC is helpful if you have a decent digital camera.

Cheers, Wizard
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