Head stack swap

[BytesBack]

Hi all,
I'm fairly new to data recovery and I was trying to get some help breaking into the industry. I have had good luck so far doing firmware repairs and PCB replacements. Head swaps, however, continue to elude me. I have been successful in removing the head stack from a drive and putting it right back in. I've gotten to the point where that works just about every time I do it, with maybe just a few read errors to show for it, definitely mostly good. It's moving the head stack from a donor to a new drive that is throwing me off. I am able to get the head stack moved over, and I am using some nice combs from HDRC to ensure the heads don't touch each other. But it seems like it never reads. Worse, when I put the head stack back into the donor drive it came from, it won't work there either.

Is there anyone close to northeast Ohio that would be willing to let me watch them do one? Am I missing a step? If not, does anyone have any tips or common tripping points I might need to be aware of? I'll go down the list of what I am doing now:

I mark the PCB, top, and bottom of both drives to indicate which is which. I remove the PCBs from the drives before putting the drive in the clean box (assume PCB and firmware has been ruled out at this point). I remove all the external screws from both drives and put them in two separate piles. I crack open the patient, check the platters for obvious damage. I remove the screws for the connector to the pcb and the magnet. I remove the magnet and loosen the PCB connector. I spin the platters while moving the armature toward the outside edge of the platters (admittedly while doing this I can feel resistance or even have the platters stop if I can't keep up a good speed.) I then remove the head parking magnet thing. I carefully align my combs and offload the head arms onto the combs, being careful that the heads never touch each other and trying to keep the combs from bumping heads laterally. I move the patient combs out of the way and repeat the above steps for the donor drive. Once I have the donor head assembly in hand, I move it onto the patient drive. I offload the heads off the combs to the platters. Here I move the heads to the inside of the platters (while spinning) and install the parking magnet thing, the order depends on the parking magnet and whether I can install it while the heads are well away from the edge or not. I the reinstall the magnet and PCB connector. I reassemble the casing and put the original PCB back on. I fire up the drive in a computer and wait for it to ID.

I should also note that I do not have a ground strap on, but the workstation I am at is electrically isolated from ground.

Any and all help is appreciated.

Steve

[thatdellguy]

and I am using some nice combs from HDRC

After my HDRC head comb tools ruined two head sets they got retired. They were a total waste of money.

[BytesBack]

and I am using some nice combs from HDRC

After my HDRC head comb tools ruined two head sets they got retired. They were a total waste of money.

How so? I don't see them as being the cause here, it's probably me. What do you use instead?

[CK]

Perhaps you are not matching your parts closely enough?

You neglected to mention what drive you carried out the swap on?

My advice is to get a Toshiba low capacity hdd (30,40GB) and try. These are the easiest to start with.

[BytesBack]

I didn't mention one drive because I have tried it on 4 drives so far. Hitachi 2.5" 320 GB, Seagate 3.5" 750 GB, Western Digital 3.5" 200 GB, Hitachi 2.5" 60 GB.

The first two I mentioned I definitely killed the heads by letting them touch. The last two, though, I am at a loss. They were identical matches in all important ways, only off by a few months manufacture.

It can't just be a mismatched head though, because it doesn't work when it goes back into the donor.

Thanks for the tip on the low capacity Toshibas!

[CK]

Don't waste your time on the WD drives, that is far more advanced. Some Hitachi's can be tricky. Stay away from high capacity drives for the moment. Remember, most pro's started on very low capacity drives - very high capacity disks are a relatively new addition.

Stick with the Toshibas and low capacity 2.5" drives until you are comfortable. You should be able to remove heads from the same toshiba time and time again.

Also, stay away from quantum disks.

[BytesBack]

I appreciate the tips, CK. I will pick up a couple of old Toshibas to try out.

What exactly is it that makes the higher capacity drives tougher? Are the heads easier to damage? Are the components smaller and tougher to move around or easier to break? Or is it just tough to get the heads to match another drive?

Thanks!

Also, Quantum? Those can't be high capacity.

[BlackST]

forget quantums and their cousins Mx740...

[granaryloaf]

What exactly is it that makes the higher capacity drives tougher? Are the heads easier to damage? Are the components smaller and tougher to move around or easier to break? Or is it just tough to get the heads to match another drive?

As capacity increases tolerances to differences from the manufacture of the heads become more apparent. As does the difference with the torque of the screws you use to secure the heads, and on WD drives there is so much play on the head spindle you can easily cause a huge alignment issue whilst replacing them (if they are compatible in the first place).

Also you need to check for damage to the platters (all platters if possible - but you can't just remove them, pick them up and check due to further alignment issues), sometimes the eye does not detect very serious problems with the platter surface.