MQ04ABF100 - Write Channel Blocking

[ddrecovery]

Hey Guys
Anyone willing to share how to hardware block the write channel on a MQ04ABF100.
I tested with a donor PCB yesterday with the two sets of lines from controller to connector.
I assumed the write channel is the line with voltage, but tried both set anyway.
After cutting the drives just hangs on BSY.
I repaired the lines after and the PCB boots up fine, so its not that I caused other damage cutting them.
Image attached of the lines cut and tested.
Not pretty as its was just an experiment.
Anyone willing to share?
Tim

Attachments

[fzabkar]

You need to find the Write Gate and disable it.

Here is a Seagate example:

https://www.hddoracle.com/viewtopic.php?p=22105#p22105

"PA_WRE - write enable"

[ddrecovery]

You need to find the Write Gate and disable it.

Here is a Seagate example:

https://www.hddoracle.com/viewtopic.php?p=22105#p22105

"PA_WRE - write enable"

Thanks for the info.
Do you have any other examples of other PCB's?
We have 1000s in stock but not this one.
I am guessing it was a Seagate test PCB looking at the silkscreen.

[fzabkar]

See the "-WG" test point on this old PCB (Write Gate, active low, top left corner, near cutout):

https://www.hddoracle.com/download/file.php?id=88&mode=view

https://www.hddoracle.com/viewtopic.php?p=135#p135

[ddrecovery]

See the "-WG" test point on this old PCB (Write Gate, active low, top left corner, near cutout):

Many thanks.
I'm sure I probably have others with similar markings.
I will do some testing.

[ddrecovery]

I just realized this is what Vlad was referring to in a previous post.
"HW block write channel (WG)"

[fzabkar]

Here is another possibility (Toshiba MK2016GAP):

https://bugworkshop.blogspot.com/2020/07/toshibamk2016gap-20gb-hard-disk-drivepcb.html

It has a discrete R/W Channel IC -- Marvell 88C4210.

Not much info here (as is usually the case with Marvell):

https://www.digchip.com/datasheets/download_datasheet.php?id=95107&part-number=88C4200

However, page 155 of this patent has a pinout:

https://patentimages.storage.googleapis.com/e6/9c/f6/d1ac4d3e7e2509/WO2004100131A2.pdf

[ddrecovery]

However, page 155 of this patent has a pinout:
https://patentimages.storage.googleapis.com/e6/9c/f6/d1ac4d3e7e2509/WO2004100131A2.pdf

Spooky, someone just sent me that one as well.
I am out of the country later tonight for a while so will pick this up when I get back.
If someone shares confidential info I won't post it unless they approve.
But hopefully we can work it out and share with everyone.

[H13]

Is it to avoide new heads writing to sa?

[Amarbir[CDR-Labs]]

Well,
How many drives have you really killed that you are searching for a hardware solution .Can some of my friends out here say really if a hardware solution is required .

[H13]

Hey Guys
Anyone willing to share how to hardware block the write channel on a MQ04ABF100.
I tested with a donor PCB yesterday with the two sets of lines from controller to connector.
I assumed the write channel is the line with voltage, but tried both set anyway.
After cutting the drives just hangs on BSY.
I repaired the lines after and the PCB boots up fine, so its not that I caused other damage cutting them.
Image attached of the lines cut and tested.
Not pretty as its was just an experiment.
Anyone willing to share?
Tim

Hi bro <<
any update here ?

Thanks