Hitachi TravelStar 7K500-250 HTS725025A9A361 NVRAM

[Dave@LDF4N6]

I have a Hitachi Travelstar 2.5" drive,
[url]http://ldf4n6.serveftp.net/images/IMG_1487.JPG
[/url]
Model: HTS725025A9A361
Made In: Thialand
P/N: 0A73352
MLC: DA3247


The top 2 lines of the PCB are:
http://ldf4n6.serveftp.net/images/IMG_1488.JPG

0A71428
DA3005A

I ran diagnostics on the drive using an Atola. I need a donar PCB and
maybe a head stack replacement as well. After some research it
appears that many of the new Hitachi drives store adaptives and other
information in the NVRAM stored on the PCB which will need to be moved
from the original PCB to the donar.

I'm not sure how to identify the NVRAM chip. Research I've come
across says the NVRAM chip is an 8-post chip and may be the U3 or U6
chip. Anothers say its the U5. Can someone identify and tell me how
they identified the NVRAM Chip on my PCB?
http://ldf4n6.serveftp.net/images/IMG_1491.JPG
http://ldf4n6.serveftp.net/images/IMG_1493.JPG

[Dmitry Postrigan]

Hello,

NVRAM is U6 on this one.

[Dave@LDF4N6]

Dmitry, thanks for your quick response.
Can you explain to me how you know this is the NVRAM chip?

Thanks,
Dave

[Dmitry Postrigan]

Dave,

Generally, 25... series chips are high capacity EEPROM chips. 93... series are low-capacity, and are used to store some parameters, hence it could be identified as an NVRAM chip.

Anyway, if you simply download .pdfs for those chips, everything becomes obvious. Here's an example for 93C76: http://ww1.microchip.com/downloads/en/D ... 21796K.pdf

[fzabkar]

HDD IC database:
http://www.users.on.net/~fzabkar/HDD/HDD_ICs.txt

[Cyclenorthman]

Hi Folks,

I'm new here and need some information on testing the electrcal connection from the pc board to the heads. I don't want to just put an ohmmeter on it as the test current may write something on the head that is unwanted. How should this be tested.


Thanks,

CNM

[gurudata]

both U3 and U6 are the NVRAM.

[pcimage]

both U3 and U6 are the NVRAM.

a) No they're not
b) Thread is ~3 years old