Why do you wnt to do this ('how destructive can it be' :-))? I susme if you remove the obvious screws on top of the HDA, the cover will come off, but it may well be stuck on the gasket. Have you tried cafeully prising round the edges with a screwdriver? -tony

Rob Jarratt wrote: And then what do you plan to do with it, once the HDA is contaminated? Or are you doing this in a cleanroom?

Rob Jarratt wrote: If you do, and there are any valuable bits on it, copy them off immediately. I've seen people do that and have head crashes very soon afterward. Given how low the flying height of the heads is, it would be amazing to NOT have a head crash at some point thereafter. IIRC, the flying height was about five microns back in those days, which was less than the size of a lot of the particulate matter in normal room air. (In recent drives it can be less than 5 nm.)

I beleive the medical profession agree to 'first do no harm', and I think we should follow the same principle. Yes, it's a non-working drive, but that could be due to a lot of things. If the faultr is on the logic board, it may be able to be fixed (there are custom ICs there, there are also a lot od standard parts). But if you open up the HDA, you are going to have a headcrash fairly soon afterwards (unless you happen to have a cleanroom...). It's best ot avoid opening HDAs unless you know you hve to. I know I'd have done a lot more tests on the electronics befroe removing that cover. On the otehr hand, if you've undone the screws roufn the outside and freed the gasket, you've let conaminants in anyway (5 micros is small, it doesn't take much a of a gap to let such particles in!), so you migth was well go the full way and take the top off. -tony

That; probably a good idea, at least for the momnet. However, as I said in my otehr message, I'd now try to sxtract hardware info, such as pinouts, from the opened HDA to assist in fault-finding on the other drives. I have neve seen a printset for any of the RDxx drives :-( I don't know if Maxtor ever released a service manual with schematics, some hard drive manufactuered did at one time (they treat the HDA and not being field-repairable, but include scheamtics, etc of the PCBs outside the HDA), others didn't. Maybe, maybe not... Here's what I'd : the lock solenoid and the positioner coil Power up an unopend drive and see if you can hear the lock solenoid operating. Check it's getting voltage beteween its conenctions. Check the voltage across the positioner coil connections. Should the heads be mocvig? You don;'t need much more than a multimeter to do that. Lookign at the XT1140 logic board (and I rememebr seeing at least 2 versiosn of that over the years), there's a row of TO22 power drives (MOSFETs? I don't think they're bipolar transistors) which I think are the spindle motor drivers,. There's also a couple of what look like audio amplifer ICs (DIL packages with a heatsink tab on each side) which I think form a full-H driver for the positionr coil. If the positioner is not gietting any drive, you might start looking aroudn the latter. -tony

On 09/17/2011 01:24 PM, Rob Jarratt wrote: Are you sure there aren't any other screws underneath the big sticker? Feel around for a "dent". Many drives have one in the middle, like over the spindle axle. -Dave -- Dave McGuire Port Charlotte, FL

Isn;t this actually a Maxtor drive? If it's anything like the dead one I've just pulled out of the junk box, there are screws under the label (and also a red plastic breaterh plug, which you cna leave0. The drive I found (an XT1140 IIRC) has 12 screws aroudn the edges of the cover which take a TX8 driver and 2 screws under the label which take a TX10 driver. One of the later is over the spindle, the other over the pivot for the head arms. The latter was _very_ tight and took a lot of shifting! For those who are interested, it's a voice coil positioner (what a suprise) operating a swinging arm assembly carryign the heads. There's aslo a hed locking solenoid. On the flexipring to the heads are 4 custom ICs which look to be 2 pairs of indentical ones,. Obviously head preamplifiers and maybe write drivers too. -tony

I've just red pivot for aslo which Yes, that matches exactly what I found. Regards Rob

Do you hafwe a clean room? Remember the RD54 is fairly high capacity and that the flying height of the heads is reduced as the bit density is increased. So I would think the RD54 is more susceptable to headcrashes from internal contaminants than many other ST412-interfaced hard drives. Have you done the obvious external tests first, like checking if there's any current trhoguh the positioner coil?If nto, the heads certianly won't be moving, and the fualt is most likely on the logic board. -tony