Floppy drive repair

[bigmessowires]

I've got several old 400K and 800K floppy drives, in various conditions that I'd like to repair. One 400K drive basically works, but makes sandy grinding noises while the disk is spinning, and occasionally gets read errors. Another 400K drive makes ominous noises when powered up, but I haven't tried a disk in it yet. An 800K drive seems completely seized up, and I can't even insert a disk.

I'm planning to clean and lubricate the drives following the instructions at http://68kmla.org/wiki/index.php/Floppy_Drive_Lubrication . Does anybody know if those instructions apply to 400K drives, or only 800K or Superdrives? The only 400K floppy specific reference I found was viewtopic.php?f=7&t=18790#p177486

When the instructions say to clean the head with isopropyl alcohol, I assume that means swab it on with a Q-tip? It seems these are very delicate and easily broken?

Most of the maintenance/repair discussions I've found are a little too high level for a newbie like me, and say things like "remove the top head assembly and clean the heads" without really explaining how to do that. From that perspective, the lubrication guide on the Wiki is great, with lots of close up photos. Thanks to whoever put that together.

Any other great words of wisdom before I begin? Thanks!

 

[NJRoadfan]

The instructions only apply to the later drives. The 400k full height drives are entirely different.

 

[sadmanonatrain]

bigmessowires,

I recently re lubricated the 400k floppy drive of my Macintosh 128k. The instructions provided are for newer, half height SuperDrives and 800k drives.

The servicing involved removing four screws from the underside of the drive. This enables you to release the disk carriage assembly from base of the drive.

Now you need to free the disk carriage assembly from the eject motor. This can be a fiddly task!

Once fully removed, you can gently wash the drive assembly of its old grease and apply some new white lithium grease.

Finally reassemble the drive and make sure it injects and ejects disks properly.

I hope this helps!

 

[bigmessowires]

Now you need to free the disk carriage assembly from the eject motor. This can be a fiddly task!

Thanks! Is there a diagram or photo of the 400k drive avenger that shows which part is which? I'm a little vague on what's the disk carriage, but maybe it's obvious once it's opened up. I'm just a little nervous about breaking it while fiddling to discover how it comes apart.

 

[sadmanonatrain]

bigmessowires,

I have created this PDF instruction guide to help collectors re-lubricate their 400k (and possibly 800k) drives.

https://drive.google.com/file/d/0B6j6P7lBWw-BNHQ4dXRYZkFGdzQ/edit?usp=sharing

I hope this helps!

 

[bigmessowires]

Awesome, thank you very much! I need to get ahold of some grease, then I'll definitely try this out.

I discovered that Larry Pina's "Macintosh Repair and Upgrade Secrets" also has a section on servicing 400K drives, but it's inexplicably part of the Lisa/Macintosh XL chapter instead of the regular Mac chapters or the chapter on disk drives. I never noticed it before.

 

[bigmessowires]

Yesterday was floppy drive maintenance day. I used sadmanonatrain's guide for the 400K drives, thanks! Though in hindsight, I think it's possible to clean and service the 400K drive without separating the disk carrier from the rest of the parts.

Drive #1 was a 400K drive from a Mac Plus. Why there was a 400K drive in a Mac Plus, I don't know! This drive had trouble ejecting - it would disengage the head and lift up the disk, but wouldn't spit it out. I took everything apart, and cleaned and re-greased it with Q-tips, WD-40, and "Super Lube" synthetic grease. I also swabbed the head with alcohol. After fiddling with it, I discovered the spring mechanism for pushing the disk out was frozen. I applied more WD-40 to the relevant parts, and pushed them back and forth with my finger a few times, and now it's as good as new!

Drive #2 was a 400K drive from a Mac 512K. It was already working OK, though it occasionally made odd sounds and got read errors. I cleaned and lubricated it the same way as drive #1, and it seems fine now.

Drive #3 was an external 800K drive. I could not insert a disk into this drive: it was like trying to push a disk into a rock. I disassembled the drive, cleaned and lubricated everything, and re-assembled, but it was still just as bad. Eventually I discovered that if I removed the eject motor, I could insert and eject disks (with my finger) just fine. As far as I can tell, inserting a disk actually forces the eject motor to turn a little, and this motor was completely frozen up. I tried squirting more WD-40 into the motor housing at the shaft opening, but I'm not sure it did anything to help. After a lot of poking and prodding, it finally freed up, and now this drive works great.

Drive #4 was a Superdrive from a Mac IIsi. At power-on, this drive made a horrible grinding noise, and it was unable to read any disks. I disassembled, cleaned, and lubricated the mechanism, but it didn't help. Observing the drive "live" as it attempted to read a disk, I noticed the head didn't seem to be moving normally and the stepper motor was vibrating. I think the motor had frozen, or else the head was stuck on its guide rails and unable to move. More WD-40 and grease were applied to all of the above. It still didn't work at first, but after about three test disks, something popped loose and now the drive works great with no more strange noises.

I have three other floppy drives I'd planned to service too, all of which were working fine, but I wanted to give them some preventative maintenance anyway. But after the first four drives I was getting tired and sore from hunching over the drives all afternoon, and decided to save the rest for another day.

Bottom line for somebody like me who's never serviced a floppy drive before: it's not that hard, and you can probably fix most "broken" drives. I thought it was going to be super-complicated, but it wasn't at all. Just go slowly and don't force anything when you're disassembling it. If you can't figure out how it comes apart, start removing screws and pushing gently on different parts of the mechanism, and after a few minutes it'll become clearer how it moves. Take lots of photos first, in case you forget how it goes back together. Apply WD-40 to all the moving parts in the insert/eject mechanism, the stepper motor gear, the rails that the head rides on, and any other place you find moving parts. Make sure everything's moving smoothly as you insert and eject a junk disk while the drive is unplugged, on your workbench.