Hitachi HTS725050A7E630 ARM Family, corrupted NVR

[Powermax]

Hi to all, i have this Hitachi Hdd with PCB problem, infact if i read NVR more times, save it in more files and after i compare it, i can see are all different. I have unsoldered patient NVR and i solder it on donor PCB. I try to read more time NVR like before, and now all files are ugual. I suppose patient PCB have somo problem on read channel of processor. After i used donor pcb with patient nvr on Hdd, now Hdd start motor but i can ear heads knock. Now i swapped heads with good ones, but hdd knock the same. I suppose patient NVR have corruption on code. I need to know if there are some way to obtain a NVR code copy from SA and if yes how i can do that.
Thank you to all.

[fzabkar]

ISTM that the original problem could have been dry solder joints at the NVRAM. If you upload your NVRAM dump(s), I could verify their checksums for you.

XOR16 checksum calculator for Hitachi NVRAM:
http://www.alexsoft.org/viewtopic.php?f=22&t=80&p=4588

[data-medics]

You might want to look at this thread: http://www.data-medics.com/forum/viewtopic.php?f=5&t=39

I've found that even with compatable PCBs the NVRAM code isn't always compatable with the actual chip. So you might have to physically move the original one.

[Powermax]

Thnks to all for suggest.

For fzabkar, i uploaded here all copy of NVR. If you can check it will be apreciated.

Tnks for help

Attachments

NVR.zip

(7.78 KiB) Downloaded 636 times

[Powermax]

I just solved !!!!

I explain what i do.
Patient Hdd with Donor PCB and Patient NVR.
Now disperate i try to rewrite NVR with another NVR from same Hdd with same Fw. version. Power on Hdd, motor start and hdd go to ready without knocking, but heads do not knock. Mmhhhh Very strange.
And now the big idea

With an HexEdit utility, i opened NVR file i used and patient NVR corrupted file, and i compare it.

I see only 430 byte of difference. I try to write on NVR file used first different block from NVR corrupted file. I write file on NVR, and power on Hdd. Nothing change, same problem.

I try to write second different block. I write file on NVR, and power on Hdd. Nothing change, same problem.

At the end i try to write third different block. I write file on NVR, power on and.................. Hdd go to ready and i can access to SA and i can recover data !!!!!!!!!!!!!!!!!

Bye to all.

[fzabkar]

For fzabkar, i uploaded here all copy of NVR. If you can check it will be apreciated.

The NV-RAM.NVR, NV-RAM_0.NVR and NV-RAM_1.NVR dumps are identical. Their XOR16 checksum is 0x0000. The other dumps are bogus.

[ROb]

Hello,
I have similar situation in Hitachi Hdd Whose NVRAM is totally Bad and Can not be Read even by READER.
PCB is Okay. With this NVRAM the HDD does not spin.
I have a similar MLC Code drive with that it starts but no SA access.
Is there a some way to obtain a NVR copy from SA and if yes how i can do that.
Thanks

[ROb]

Can one share the Compatible NVRAM for this.
Or any other way to start this drive.