HDT721010SLA360

Sam

Member
Damaged heads, contamination on all surfaces inside drive. Media damage rings H1. Cleaned all platter surfaces, swapped to new base, bent H1 back on donor head stack.

I thought that by disabling H1 in NV-RAM drive would come ready and ID normally but this doesn't seem to be as straight-forward as, for example, disabling a head on a Seagate.
With H1 disabled in NV-RAM, utility will only start with loader. I was able to back up all FW mods in this mode. However, drive does not ID and has 0 capacity.

As an experiment I took a good working donor, bent H1 back, disabled H1 in NV-RAM. Acts exactly like patient.

Head map on this model is listed backwards in NV-RAM: 05 04 03 02 01 00. Found this by using another working donor (with no heads bent back). By disabling H1 in NV-RAM (05 05 03 02 01 00) drive takes a couple minutes to become ready but eventually does start utility in normal mode and IDs with full capacity. For that matter, I also disabled all heads but 0 (05 05 05 05 05 05) and eventually comes ready and IDs with full capacity. Changing first position to anything but 05 results in drive staying busy.

So far my conclusion is that on this model, if a head is disabled in NV-RAM, it still needs to find the servo markers for that head before it will ID. So if a head needs to be bent back to avoid media damage, the drive will never ID. Hopefully I'm wrong.
Also, doesn't look like hot swap/smart donor methods work for this model.
 
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