HITACHI HDT721016SLA380 Having DEAD Pcb

[ROb]

Hello All,
This a continuation of the following thread as requested

viewtopic.php?f=1&t=12207&start=40

Just to recap, this drive has a bad PCB and Bad ROM. With the Donor PCB and adapted NVRAM using PC3K i am able to gain SA access and able to copy NVRC module.
But unable to Start the drive, may be i am missing onto correct method or technique.
With some hints i shall be able to resolve it.
Thank you all for your replies.

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[Suitsof]

....With the Donor PCB and adapted NVRAM using PC3K i am able to gain SA access and able to copy NVRC module.

So what is the problem?

[fzabkar]

If I were approaching this problem as a novice, I would try to understand what happens when the drive powers up. To this end I would determine which SA modules are loaded and in what order.

For example, if you replace the PCB NVRAM on the donor drive with its NVRC SA copy, does it start correctly, or does it produce the same symptoms as the patient? If the symptoms are the same, then the problem must be due to differences in the NVRC module. FWIW I have examined the NVRC and NVRAM examples from an HDS721680PLA380 and have found a minor difference in the mu-code, CRC bytes, and a single byte at the end of the NVRAM (which is not subject to checksumming).

I notice that in the other thread you have the following report from PC3K:

Code:

Loading modules table................................................. : Ok
Loading the table of "open" modules................................... : Error
Error : .............................................................. : Error executing loading "open" modules dir command
Loading zone allocation table......................................... : Ok

AIUI, the "modules table" refers to the USAG/RESF SA module, "zone allocation table" refers to the ZONE module, and the table of "open" modules is a directory of modules within the OVR1 module.

This would suggest that something may be wrong with the loading of the OVR1 module, yet all its copies appear to be OK.

[fzabkar]

Did you compare the ROM (eg ROM0A70A) and NVRAM (eg E2PRP21NN70A) versions?

[ROb]

Thanks fzabkar for your help and direction
I could resolve this issue with modifications in NVRC