Fix Mitsubishi mf355 floppy drive

[aserker]

Hello everyone,

I've recently acquired a Mitsubishi MF355F 3'5 1.44Mb floppy drive, which was in quite a dusty state. According to the previous owner it was previously used in a Performa 5200.

Before even testing it, I carefully cleaned it using Q-tips and isopropyl alcohol, then reapplied grease to moving parts.

I installed it in a Macintosh SE/30, but it fails to read known-good floppies. Instead, macOS prompts me to format the floppy.

Here's where it gets strange:

• Formatting completes without error.
• After formatting, I can write and read files on the floppy using the same drive and create a working boot floppy.
• However, the floppy is unreadable on any other floppy drive.

Could this indicate head misalignment due to cleaning? Unfortunatly I didn't test before cleaning to tell. While cleaning I refrained to unscrew anything. However I think I may have rotated a bit the endless screw of the stepper motor with the cue tip. Any advice on what to check or how to recalibrate the drive would be greatly appreciated.

I think I should

Thanks!

 

[aserker]

 

[aserker]

 

[aserker]

Problem Solved!

I finally decided to go ahead and try realigning the stepper motor.

I slightly loosened the screws on the stepper motor, just enough to rotate it by a degree or two clockwise. After that, I restarted the machine with a known good floppy disk to see if the drive could finally read it. It didn't work on the first try, but amazingly, it did on the second!

This was really just lucky, I guess.

If you try this yourself, keep in mind you might need to rotate it counterclockwise.

Next time I do this kind of repair, I think I'll make a mark to help me see how much I've rotated the motor.

 

[aserker]