Ok, have about 2 working Maxtor 6y160M0 drives and encountered a Refurbished maxtor 6y160P0042811 K, G, C, D (4 head, thankfully) I have replaced with a head stack from another 6y160P0042811 K, M, C, D but no still love. Original problem seemed to be a bad head on other than head 0 as it would show on bios, but after head stack replacment drive just clicks. Codes are identical YAR41BW0 on both drives.
Put the transplanted heads back in the original drive just to "be sure" and they worked fine. Re-transplanted AND moved PCB from the non refurb drive, still click of death.
I only have access to small university cleanroom (well, clean box, with rubber hand holes in the wall, really!) enviornment, and am a lowly tech.
I am thinking something in the firmware, maybe, since it is a refurb drive? Usually headstack replacement works just fine for me on these drives (non refurb) but this is the first refurb maxtor I have encountered that needed a headstack replacment. I have done this successfully on maxtor Diamond plus 8, 9, 10 about a dozen times.
I also have spare YAR61HW0 (6Y160M004725A) (sata DM Plus 9) and on a lark swapped PCB from known good DM9+ pata to this drive. worked fine. Also put the PCB from this on known good PATA drive. Worked fine. (I thought that was interesting.)
I guess I'm wondering if I should attempt another head swap, or send off to the big boys. I called one outfit and got the lowball quote then I gave them the "well, we had someone try a headstack replacement and because this is a refub drive, it is apparently "special"" and the quote was suddenly much more

Does anyone have any ideas out there? I'm suck and an unsolved puzzle drives me up the wall. Much appreciated.