Macintosh Classic Floppy Drives - auto-inject.

kallisti5

New Tinkerer
Aug 6, 2025
2
2
3
I just finished restoring my Macintosh Classic (new caps, retrobrite case). It's working perfectly minus one thing... the floppy drive.

While cleaning it, I didn't realize how little upward force it took on the heads to "bend" the spring steel to permanently deform it. I tried the "inserting a rod at the spring steel and bending it back downward" trick, but my lovely MP-F75W-01G is still non-functional.

Next comes Ebay. Whoo whee, the auto-inject drives are expensive.

A replacement?
As I look over at my Performa 6400 with extremely brittle plastic that creaks when I look at it... I see it's floppy disk drive (MF355F-2592MA). Pull it and it looks like it will work! Exact same interface... except the drive is not auto-inject. You can't push the floppy disk into the drive through the front case slot (and there's no way in hell i'm modifying the case of my Classic)


A repair.
Running towards the end of ideas, I found a bunch of Sony MP-F73W-01D drives on Ebay. They're a similar generation and support a similar range of floppy disk sizes. They're also substantially cheaper.

I'm going to try transplanting a head assembly from the MP-F73W-01D into my otherwise perfect MP-F75W-01G. If it works, I may have two other head assemblies i'll post for sale here for a minimal cost if anyone is interested.
 
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vtgearhead

Tinkerer
May 1, 2023
77
28
18
Burlington, VT USA
Earlier this week I did the same thing to one of my SuperDrive mechanisms. After a bit of shameful language, I realized the little coil spring inside the head assembly had several notches available to increase head pressure. Moving it up to the next (higher) position was enough to do the trick and the drive is again working correctly. There is a video on YouTube that walks through the entire process of disassembling the drive and removing the head assembly.
 

kallisti5

New Tinkerer
Aug 6, 2025
2
2
3
Ha! I think I actually just fixed it. Did a little more bending of the heads with the drive out of the Classic and finally got the drive to read a floppy disk.

I'm still not sure if it's aligned properly, so might still replace the heads with the potential donor drives I bought.
Given the cost of the auto-inject drives it would be a nice data-point to be aware of.