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I have a Sony HD 3.5″ floppy drive. It isn't reading properly and IMD shows the rpm to be 150-200.

I dismantled the drive and there was a sticky ‘goo’ on the bottom of the inner ring that sits inside the spindle assembly directly next to the direct drive magnets.

I cleaned it off, I think quite well, with IPA and cotton buds but the drive seems to be even stiffer and now struggles to spin at all.

Should there be some grease here or is something else wrong?

Thanks!

Floppy motor

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    "I cleaned it off with IPA". Beer does not generally make for a good cleaning agent.
    – dave
    Commented May 15 at 12:02
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    crap, should have used cider ;)
    – squelch41
    Commented May 15 at 12:11
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    I am no trilobologist, but, before you select a lubricant, I would keep silicones away from anything that does not specifically need them as the silicone component can stick to surfaces—in which I would include the drive heads and discs—so well that it needs mechanical removal (like sandpaper). IMHO. Commented May 15 at 19:08
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    apart from the mechanical problem, your photo looks like the tachometer trace pair (the zig-zag trace) is damaged at the right side, near the PCB label saying "PF4". If this is indeed the case, speed regulation is not going to work at all. Commented May 15 at 20:06
  • WD40 can fix anything! Possibly even cancer :-)
    – paxdiablo
    Commented May 20 at 0:01

1 Answer 1

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It sounds like you've cleaned-off the lubricant grease that is there to facilitate the movement of the rotor. It was almost certainly the original factory-applied material, and therefore likely to be fairly dirty after years (decades?) of use - hence it performing poorly.

Removing it entirely was good, but only as a first step - you now have to apply some new clean lubricant (I'd suggest lithium grease if you can find some) so that the moving parts can in fact move.

Here's a YouTube video showing how to correctly service floppy drives like yours.

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    Ideally you would provide a description of the technique described in the YouTube video, rather than just link it. Google isn't great at keeping YouTube videos around.
    – wizzwizz4
    Commented May 15 at 17:34
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    grease doesn't seem to have helped - still high resistance once rotating part goes all the way down the axel. should there be a spacer? It almost feels like the rotator is sitting too low on the spindle
    – squelch41
    Commented May 15 at 19:11
  • Unfortunately, the video doesn't help as it's about him fixing the eject, not the spindle on an auto-ejecting apple drive
    – squelch41
    Commented May 15 at 19:25
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    @squelch41 I don't know this exact drive mechanism, but I'd certainly expect to see one or two low-friction washers, such as those made of PTFE, to be found on the spindle. This would reduce the friction between the front face of the stationary brass bush visible in the photo, and the mating face of the rotating assembly that goes into it. Small washers like these can easily fall off and go missing during disassembly. Commented May 16 at 6:28
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    @wizzwizz4 My answer is a non-link-only theory and suggestion to remedy the problem posed in the question, along with a link to a video which might provide more insight. I'm not about to transcribe that video into my answer, and if we're all so terrified of link decay we should demand nothing but explicit and fully-complete answers with no link feature at all. It's like nobody knows what the REASON for hyperlinks is any more. Commented May 16 at 17:09

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