Floppy not reading. Nuts.

[SpocksBeer]

Hello all.

I have a Superdrive in an SE/30 that's not reading or initialising disks. Two in fact, but I'm only looking at one at the moment. Fortunately I have a known good drive that does work with this machine, so the logic board is good.

With this drive I've cleaned and lubricated it, but it did not change the behaviour. Comparing it closely to the working drive, it appears the top read head is a bit springy and not clamping properly. With a little weight, specifically two M6 nuts, the drive does in fact work. Not an especially elegant solution, mind:


So, impractical solutions aside, can this be fixed permanently? Can I just take that head assembly off and give the metal part a little tweak, or does some special care need to be taken here? The weird star screws that are holding it together scream "don't disassemble me bro" - but also I can't really make it worse at this point (probably). What size and shape is that screw head pattern anyway?

Cheers!

 

[bibilit]

Yes you are right, both parts of the head should not be disassembled.

The head has been probably lifted and is not coming back in contact with the disk anymore.

On the back of the head, you have a small spring, you can try moving the spring around to clamp it closer, but it's hit or miss.

 

[SpocksBeer]

Ah, cool, I didn't notice a spring on either the working or not working drive back there. Will look closer tonight, thanks.

Might be a reason to figure out how to make a new spring.

 

[SpocksBeer]

Win! Found the spring, figured out how to disassemble the head assembly (seek motor out, couple of extra screws, then the whole head assembly is free). There were three notches, and the spring was already in the optimal position for tension:


So I carefully cut a fourth notch with a blade and moved the spring over:


Reassembled, and now reading disks fine. I know I'm probably going over ground well trodden, but always good to have a quick win. Thanks for the pointer @bibilit

 

[SpocksBeer]

Spoke too soon. It reads some floppies some times, usually just as far as opening the disk and showing the files. IO errors when actually reading the files.

Guess I'll look into spring making...

 

[croissantking]

Spoke too soon. It reads some floppies some times, usually just as far as opening the disk and showing the files. IO errors when actually reading the files.

Guess I'll look into spring making...

See this video by Branchus Creations starting at 39:05. He talks about adjusting the leaf spring after the top head is lifted too high which should help you.

 

[SpocksBeer]

Thanks, I'll give that a shot too. Just have to disassemble everything again, I got too excited. Sigh.

 

[SpocksBeer]

Well, good news. I reset the spring and tried Bruce's method, but it made little difference either to the clamping force (which looked ok both ways), or to the results.

Then I went back to the known good drive with the same disks and lo, same errors. I was just dealing with failing media, possibly as a result of a close encounter with a magnetized screwdriver on my workbench, or maybe just age. Annoying, but at least it's not a dead drive.

Now onto the next one. Similar symptoms as the first - no reading, failure to initialise disk - but after pulling it out, and with what I learned on this one, the heads look ok. Mechanism works smoothly, although it's not been lubricated yet, and it's pretty clean. Seems to be able to tell the difference between a Mac and non Mac disk (given the different error messages in system 7), but goes straight to "this disk is damaged" when a known good (ha) disk is inserted.