Toshiba MQ04UBD200 compatible heads ?

[michael chiklis]

Hello,
i need to swap heads on a MQ04UBD200 patient drive.
I've a MQ04UBD200 donor drive, i need to know if in your opinion heads are compatible with the patient.

Donor drive is 37 months older than patient.
Donor Cyl num: 361612
Donor SPT: 3632

Patient Cyl num: 355807
Patient SPT: 3840

[DRUG]

I do not believe they are compatible.

[melvin]

I do not believe they are compatible.

Why not? I would use them.

[DRUG]

I do not believe they are compatible.

Why not? I would use them.

Even though Toshiba are easier to be compatible I think drive rev and drive age are too diferent.

Anyways, OP can test and let us know.

[melvin]

I often use Toshibas that are five or more years different. That's their beauty. Not like Seagate which are different every week.
Good luck for OP and hope this donor will work.

[pcimage]

I do not believe they are compatible.

Why not? I would use them.

So would I.

[unknown]

Me also see no problems with it.
But the surprises comes after swapping heads.

Good luck.

[michael chiklis]

I will try and let u know.

[Doomer]

I almost never had a problem with 2.5" Toshiba heads compatibility in terms of data reading. However non-original heads almost never write properly, they usually kill-on-write in system area. Might want to keep that in mind when you change the heads.

[pclab]

I almost never had a problem with 2.5" Toshiba heads compatibility in terms of data reading. However non-original heads almost never write properly, they usually kill-on-write in system area. Might want to keep that in mind when you change the heads.

Hey Doomer

Care to explain the Kill-On-Write situation? what does that mean?
Thanks

[fzabkar]

I almost never had a problem with 2.5" Toshiba heads compatibility in terms of data reading. However non-original heads almost never write properly, they usually kill-on-write in system area. Might want to keep that in mind when you change the heads.

Hey Doomer

Care to explain the Kill-On-Write situation? what does that mean?
Thanks

Let me guess. The microjogs are too different, resulting in the donor write element positioning itself too far off the SA track centreline?

[Doomer]

Care to explain the Kill-On-Write situation? what does that mean?
Thanks

Once a sector is written it becomes unreadable and data in it is gone.

[michael chiklis]

When we do data recovery we don't write anything on patient UA.
On Toshiba drives there isn't much to modify on SA, maybe only g-list reset but i will not reset it because i use mrt and i know that it has a bug which everytime corrupts g-list module.

[Doomer]

On Toshiba drives there isn't much to modify on SA, maybe only g-list reset but i will not reset it because i use mrt and i know that it has a bug which everytime corrupts g-list module.

So far it sounds like you don't have enough knowledge/experience to work on this model (this is an SMR drive)
I suggest you experiment with heads transplant on a donor first to better understand the consequences.

[michael chiklis]

So, you're saying that there is something else that needs to be done on SA on this type of hdd before we start cloning?
I've not seen any topic on acelab blog or on this forum about kill-on-write on SA.

[michael chiklis]

I found this:
https://forum.hddguru.com/viewtopic.php ... 99#p293999

Code:

HW block write channel (WG)

What does it mean?
Do we have to short write channel?

[michael chiklis]

or isolating (cutting) write trace from HDS ?

[fzabkar]

I found this:
https://forum.hddguru.com/viewtopic.php ... 99#p293999

Code:

HW block write channel (WG)

What does it mean?
Do we have to short write channel?

IIUC, you need to prevent the Write Gate (or Write Enable) signal from being activated. This signal enables/disables the write amplifier. Depending on the preamp, it may be possible to achieve the same end by opening the negative supply. AIUI, the negative supply is required for writing but not reading, but it's unclear whether the preamp would register a write fault without attempting to write anything.

[pepe]

so lack of -supply would not result in clicking...
(which was the case, at least on older drives, not sure about MQ04 coz didn't test it...)

pepe

[michael chiklis]

I found this:
https://forum.hddguru.com/viewtopic.php ... 99#p293999

Code:

HW block write channel (WG)

What does it mean?
Do we have to short write channel?

IIUC, you need to prevent the Write Gate (or Write Enable) signal from being activated. This signal enables/disables the write amplifier. Depending on the preamp, it may be possible to achieve the same end by opening the negative supply. AIUI, the negative supply is required for writing but not reading, but it's unclear whether the preamp would register a write fault without attempting to write anything.

How to open negative supply to prevent write enable?
Pcb number is G4311A.