Took apart Quantum Prodrive LPS

poiihy

macrumors 68020
Original poster
Aug 22, 2014
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After I found out how to turn on my beige G3 PSU without mother board, I tested the hard drives. One didn't work so instead of putting it back, I thought i'd just take it apart and end it. This is an 80mb (megabytes) Quantum Prodrive LPS. It uses the SCSI bus. A while ago, soon after installing OS X for the first time and before transporting it, the ProDrive suddenly stopped appearing out of the blue. I didn't bother with it; 80mb is nearly useless.

So I took it apart... I thought it would be easy to take apart because it used phillips screws. There was a torx screw in the center attached to the spindle center, and a hex nut on a special screw that holds the actuator in place.
These two were the easiest to remove, ironically, the phillips screws were hard. They were so stuck! I managed to remove most screws with a drill (screwdriver bit, not actually drilling it), but two screws were so stuck and became stripped. I had to drill those (with an actual drill bit, not screwdriver bit) to break them off.

Inside there was a dark brownish-purplish (hard to describe) disk. Two disks actually. And there was the actuator and read/write head. Very big heads compared to high density drives. It had white pads that slide on the drive.

This drive had something weird that I have never seen in a drive before. It had some weird mechanism on the other side of the head... I think it was some sort of sensor to detect the position of the actuator head. The actuator has a bar sticking out with a piece of glass with some stuff printed on it, and this glass went above another grayish-brownish printed piece of glass and underneath that was some sort of sensor. Facing parallel with the two glass was some some of light bulb... no idea what it is.

There was a plastic lock that locks the heads when the disk stops moving. It is spring loaded, and it reaches out between the disks, so when the disks spin, it makes a breeze of air which pushes this plastic thing and unlocks the read/write head. When it stops the spring pushes the thing back to lock the head.

When I opened this drive, the read/write head didn't move at all. After fiddling with it for a bit it started to move after turning it on like it usually would do. I think the lock was stuck so it couldn't move. Maybe this was why the drive didn't work.

So then I started taking it apart. First was the top magnet. There were two large neodymium magnets :D . Between the magnets were two rubber bumpers to hold the read/write head within range. I found that one of the bumpers had sort of... liquified... and became a disgusting goo. :eek: It leached over the magnet and a but on the actuator coil. The other bumper seemed a little icky but was still intact.

When I removed the top magnet it also came with a bumper (one bumper attached to the top magnet and another bumper attached to the casing of the hard drive) so the read/write head was able to move farther. I moved it and it popped off the disk, and couldn't get them back on. After removing some more parts I was able to move it completely off the disk.

Next I took off the platters. Both platters had some sort of number printed on the centermost part, right under the clamp of the spindle. Inbetween was a nice round, shiny, and light aluminum spacer.

I took out the rest of the parts... bla bla bla, including that weird mechanism I already talked about.

I took out the motor and played with it. I put the disks back on, connected the motor to the board, and powered it up, and I made myself a gyroscope! :eek: :D Because the cable to the motor was short I couldn't move it far. Then a tragedy happened... The gyroscope thing tilted too far and touched the board and crashed. Soon after I found that the motor cable had ripped!!! :eek: :(

Well that's about it... this time I kept the actuator as I plan to turn this into a hard drive speaker :D But soon afterwards I realized that I had ripped off a rubber bumper from the magnet... and a hard drive speaker requires the magnet... maybe I can still make it, I don't know, I'll see when I try.

Oh also... the logic board had a removable chip with a sticker that said "DisCache" so I assume this is the cache? Why is it removable? Does it store a map of all the data on the disk?


Now I have some questions.
How do I fix this motor cable? It has many wires, unlike a typical motor with 3 or 4.
What is this weird mechanism? I think it is a sensor mechanism to detect the position of the read/write actuator head.
What is this weird bulb? It looks sort of like an LED but it is made of glass (I think) and it has a metal sleeve around it.

Here is a video of the hard drive

It made a funny whine noise that sometimes got louder and softer. I think it's failing ball bearings.



And pictures (click to view)

http://postimg.org/gallery/u4y211jq/













These pictures were taken with an iPhone 5. The camera is AMAZING, it is SO MUCH BETTER than an iPad 2 camera... but the focusing is terrible :p
 
Last edited:

poiihy

macrumors 68020
Original poster
Aug 22, 2014
2,273
40
Does anyone know what the bulb thing is? How would I fix this motor? And why does the motor have so many wires? What is this mechanism next to the actuator? Other hard drives dont have this

Someone say something :(
I need answers!
Or comments

Also does anyone have any ideas to make out of these parts besides hard drive speaker or fan?
I wanna turn the motor into a fan.
I'm thinking of tracing the circuitry for the motor, then rip everything else out (or at least disconnect it) then I will have a stepper motor driver.
To fix this cable, I think I would first cut them straight, then sand both sides so that the wires are exposed. Then press them together and tape it, though that may not be enough, so maybe make a screw-clamp on it.
 

poiihy

macrumors 68020
Original poster
Aug 22, 2014
2,273
40
The Quantum ProDrives used rotary voice coil head positioners; I'm pretty sure the LPS did too. They're not steppers. Because it's not a stepper, it used an optical encoder to determine the head position.
Why don't newer drives have that mechanism?
 

poiihy

macrumors 68020
Original poster
Aug 22, 2014
2,273
40
Not sure what you mean. Nearly all newer drives use voice coils to drive the actuator, because they are cheaper now. Earlier the price was prohibitive so only higher performance (i.e. more expensive) drives used voice coils, and cheaper ones used steppers. Higher recording density actually just made stepper motors less useful for head positioning.
No I mean the optical sensor mechanism to detect the position.
 

poiihy

macrumors 68020
Original poster
Aug 22, 2014
2,273
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Because there all are sorts of different technologies to use, with associated patents and licensing. Piezo sensors, capacitance, Hall effect, and I believe Texas Instruments even pioneered "just read the disk to see where the head is".

Seagate didn't even widely use voice coils until they purchased Imprimis from CDC for a line of "high performance/high capacity" drives.
I see now