2 of my Hard drives crashed due to faulty SATA connector cable (it was passing high voltage). I have the chips and ICs burnt. I have found very very similar PCBs wanted to know what to do to make it work. Only experts answer.

PCB 1 details: 750GB Segate SATA

Model Number: ST3750330SV
Firmware: SV16
Date Code: 08396
Product of Thailand.
Site Code: KRATSG

PCB Number: 100466824 REV B
VCM Controller or SMOOTH CHIP number: 100439116
MCU or Big Chip: TTB5501D
Memory Chip: 1st line: W9425G6DH - 5 2nd line:08075 3nd line: 67400V900


PCB 2 details: 250GB Segate SATA

Model Number: ST3200310AS
Firmware: 3. AAC
Site Code: WU
Product of China

PCB Number: 100468303 REV A
Smooth Chip number: 100369972
BIG CHIP number: TTB5041A0
Memory Chip: 1st line: SAMSUNG 737 2nd line: K4S641632K - UC60

After contacting 5 different people who sell PCBs I could find almost matching PCBs. I have to narrow it down now to order.

My PCB 1 pictures

PCB 1: 750 GB SATA, PCB number: 100466824 REV B

Damaged HDD below



Hi resolution of the above pic here http://farm5.static.flickr.com/4070/4527833363_c815ec3761_o.jpg

Memory Chip of the PCB below



Replacement PCB- 1 in working condition below



Memory chip of working PCB below



Questions regarding PCB-1

As it a physical PCB there is no way to match the firmware and other details but I am guessing since it is an almost identical physical match I don't need to worry about firmware and other details. The MCU(the main chip or BIOS) are identical which contains the firmware version which matches Below are the details which matches with the working PCB

PCB Number: 100466824 REV B - Matching. Dealer is not sure of the REV number but he says doesn't matter (can anybody confirm this?)
VCM Controller or SMOOTH CHIP number: 100439116 - Matching
MCU or Big Chip: TTB5501D - Matching
Memory Chip: 1st line: W9425G6DH - 5 2nd line:08075 3nd line: 67400V900 - Doesn't match

I have a local expert who is going to do the hot air soldering for me. As everybody says all I just need to do is take the MCU(i.e ROM in this case as it is embedded in the MCU) from the patient drive and fix it to the DONOR and it should work.

My concern is the Memory chip doesn't match at all but PCB dealers say that it is not required, how true is this ?

For PCB-1, REV and Memory chip doesn't match - Can i go ahead and get the PCB and start the replacement process ? Also note we are not sure of the Firmware, site code and date code. My local tech can do firmware cloning as well.

PCB 2 question

PCB Number: 100468303 REV A - Matching. Complete Match
VCM or Smooth Chip number: 100369972 - Matching
MCU or BIG CHIP number: TTB5041A0 - Matching
Memory Chip: 1st line: SAMSUNG 737 2nd line: K4S641632K - UC60 - Doesn't match

Damaged PCN Memory chip image below




Replacement PCB Memory chip image below



Memory chip doesn't match here either but PCB, Smooth CHIP(VCM), MCU are a complete match.


My Local expert here says that if I just get exact Memory chip and Smooth chip (VCU) is what is needed but then again he thought that I am just getting ICs back then. Now I am getting the complete PCB board itself.

So my Major questions are

1. Do i have find exact match for the Memory chip as well ?

2. How important is the REV number for PCB - 1 as it doesn't match

3. Do I have to worry if the firmware matches, date code/site code matches or not ?

4. If my research is correct then I can go ahead and order these PCBs and have the ROM replaced from patient and donor and that should do the job, Am i correct ?

I would really appreciate if somebody can explain it to me in detail and correct me where I am wrong.

The firmware actually resides in a reserved area on the platters. The MCU has some minor bootstrap code which retrieves data (and additional code ???) from the 8-pin serial EEPROM chip near the connector end of the board. The bulk of the code is then fetched from the platters and executed in RAM.

So, in case #1, you would only need to transfer the 8-pin serial EEPROM chip from patient to donor. This chip stores unique drive specific calibration data. You should also test the motor windings for opens or shorts.

In case #2, you may only need to remove the shorted TVS diode near the power connector. This diode sacrifices itself to protect the PCB from overvoltages. Your drive will run OK without it, but it won't have any protection on the affected rail.

You don't need to match RAM chips, as long as they have identical capacities.

The following articles should help you identify the components:

http://hddscan.com/doc/HDD_from_inside.html
easy-faultdiagnostic-troubleshooting-must-try-t12319.html