I’ve got a dead hard drive (the infamous IBM 75GXP, and if you’ve got one, back up NOW) and would like to tear it apart and make a demo out of it. That is, I’d like to make the motor spin, and the head go back and forth. Of course, I will not be saving data on it.
My question is - how are these motors and head actuators driven? There are actually four wires going to the motor. Is it some sort of stepper motor? How does one “drive” the head?
Just trying to make something positive of this expensive and painful remnant of seven months’ worth of not-backed-up data.
There is such variety. The motor to make it spin will likely have two wires, but the actuator could be a ribbon cable or a hard circuit. I love taking the things apart, just gut it for the toys if it doesn’t have the setup you want, another dead drive will come along. They have the world’s best fridge magnets at the butt end of the arm. You can hold them an inch or so from a metal surface and then let go THWAAAPPP! they’re hard to get off if you don’t have nails. The tiny motors run fine for short busts with 9v batteries, so they are good for typical electric motor amusements. The platters are fun to see how far you can throw them, or for old fashioned doctor’s costumes. Since the variety, I couldn’t tell you more on the guts of the 75GXP, but I suspect you’ll have no problem powering the motor, but you’ll run ino problems with the arm. Have fun. Buy some small torx head srewdrivers.
If you have a spare PS someplace, you can just plug it in. It should do some seeks on startup. You can then drop koosh balls on the platters and watch them spin off randomly.
I once played around with the input ribbon to a dissassembled hard drive. I was never able to get the platters to spin but I could get the arm to shoot back and forth.
Oh, and watch out with those magnets…they’ll crack if you let them fly together.
That ribbon is for the read/write heads and the voice coil for the arm. The motor is usually soldered directly to the controller board itself. The newer drives I’ve seen have pins sticking out the bottom of the case block into… uh… recieving holes in the board.
I just thought - if this demo is a semi-permenant kind of thing, you’ll want to cover the top. Otherwise, two things happen. Firstly the dust settling really messes up that perfect-polish disk surface, and secondly, the top head will drag in the dust, scratch the disk and break off.
Oh yeah - the magnets for my disk are being used in an earthquake detector, but it looks like shoving a small alternating current through the voice coil might make an interesting back&forth display if you don’t want to depend on the hardware to work things for you.
Thanks for the replies. I’ve actually already used magnets from a prior drive in my 1/32 scale slot cars - they are STRONG. The car will hang upside-down from a piece of track. Needless to say, it’s fast around the track, but not very challenging to drive (WFO all the time).
I’ll just apply voltage here and there to this thing and see what happens.
capn
and I’m not kidding about backing up your data regularly if you have one of these drives - they are notorious. I shoulda known better.
