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3-1/2 floppy-drives not responding to floppy being inserted when not attached to a PC

GearTechWolf

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Was doing some cleaning (disassembly and running a cleaning-disk through them) and low-level testing (hooking up to a power-supply) of my loose floppy-drives recently, scared up twelve laying around.
Eight of them do a head-to-zero check and/or spin when a floppy is loaded, four do neither.
I know some old/early 5-1/4 drives would only spin/attempt to read a disk when commanded to by the computer, are there also 3-1/2 drives like that?
The four are various makes: A Sony MPF920-Z, an HP D2035-60021/EPSON SMD-1340, an EPSON SMD-300, and an ALPS ELECTRIC DF354H090F.
I will eventually be testing them all hooked up to a computer, but figured I'd seek info here in the mean-time.
Are PC-standard floppies dependent on the controller in the computer for self-testing, do they have some capabilities built-in, or does it vary?
Currently, I'm thinking it's the latter. Thoughts?
 

hmb

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I've never seen a 3.5" drive that doesn't at least try to index a disk when inserted.

"GearTechWolf" has these 3.5" drives hooked up to power but not to a controller - and is wondering whether in that situation the drive should "do anything" if a disk is inserted. My recollection of what happens when I have (inadvertently) done this is some 3.5" drives will run the spindle motor for a few seconds - but that's it.
 

Timo W.

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I've never seen a 3.5" drive that doesn't at least try to index a disk when inserted.
When not attached to a PC? All drives I ever had just rotate the spindle so that the spring-loaded carrier snaps into place. That's all they do on their own.
 

GearTechWolf

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By this metric then, I suspect these drives may have an issue. Could still be that they're cheaply built and had that feature removed for-cost-cutting.
Simply only indexing when initialized by a computer. But that'll have to wait until I set up a computer for testing. Perhaps the 386 I fixed recently.
 

GearTechWolf

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Okay, out of twelve drives I rounded up from various storage-spaces, ten function properly. Not bad.
One, a Panasonic JU-257A606P, has a slightly mangled spring-frame around the upper head and I *think* that's its issue.
It mostly functions fine but always fails at random points in the sequential R/W tests.
The other drive, a TEAC FD-235HF, is a more curious/uncertain failure.
It won't even start any of the diagnostics, failing with an "BAD Address mark" error every time, be it a R/W or speed test.
More strangely, sometimes the BIOS won't recognize it's plugged in, specifically if a disc is already inserted during initialization!
If the disc is out, it sees the drive and is fine until failing the diagnostics.
My question is, does this mean one of the heads has failed? It never gets past head 0 in the diagnostics.
Short of swapping the logic-board or the heads with its twin (I have a second such drive) I don't know how to pin down the error, but I'm fairly sure it's one of those two as it's apparently related to reading from the floppy disc.
 

Chuck(G)

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I don't know what you're using for diagnostics, so I don't know exactly what precipitates the error. But it would seem that "bad address mark" would indicate that the drive is seeing something, but that it's not right.

I assume that you're using a PC booted into MSDOS for you tests.
 

GearTechWolf

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I don't know what you're using for diagnostics, so I don't know exactly what precipitates the error. But it would seem that "bad address mark" would indicate that the drive is seeing something, but that it's not right.

I assume that you're using a PC booted into MSDOS for you tests.
Not quite DOS, actually! I'm using the built-in diagnostics of my 386 (CPU-3216SX) motherboard.
They include formatting a floppy, a speed-test, a random R/W test, a sequential R/W test, and a line-change test.
All require a FAT-formatted floppy, including the formatting oddly enough. It wouldn't reformat a MAC-formatted floppy.
 

GearTechWolf

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Welp, I was going to try the ImageDisk program on these defective drives this morning but ran into a frustrating issue. Well, issues, plural.
First, for some reason I have yet to understand, linux is telling me I don't have permission to write to the BLANK floppy in my USB floppy-drive.
Second, while wrestling with that, I decided to run my cleaning-floppy through said drive. Now it won't read floppies anymore!
So, I'm SOL on creating any new floppies until I fix or replace that. I'm guessing the heads are buggered now. Damn fragile cheap junk.
*MAYBE* I can rig a different drive up to the USB controller and kludge something together, but I highly doubt it.
Based on my disassembly of a different-brand non-working USB floppy, the controller and the drive electronics are likely one and that same.
Has anyone ever produced or built a universal external USB enclosure that a standard 34-pin floppy could be mounted in?
It'd need a separate power-supply of course, since USB only supplies 5V. (likely why the electronics in the USB units are all-in-one)
Anyhow, that's it for this thread until I get that miss resolved one way or another.
Final tally: Initially, 12 drives tested, 10 functional, one CRC Error (head alignment?) and one Bad Address Mark (failure in drive electronics?)
Found another complete drive in my shed, it doesn't so much as twitch no matter what I do, just gives timeout errors.
Cat knocked two drives off the table. The one whose cover bent and absorbed the impact is still fine, other developed a CRC Error issue.
So, adjusted final tally: 13 drives tested, 9 functional, 4 nonworking, and I found parts to four more drives in the shed, currently incomplete/untestable.
That's just the standard-PC 3-1/2 drives that aren't currently installed in a computer, of course. The 5-1/4 are a whole other matter.
 

jlang

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Something like this may help

IYSHOUGONG 1.44MB 3.5" Floppy Drive Connector 34 PIN 34P to USB Cable Adapter PCB Board​

 

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GearTechWolf

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Yeah, that'd be handy, thank you!
Fortunately, I jumped to conclusions. USB-floppy still works, I just had to format the floppy to access it and now have permission to put files on it.
Not sure why linux is so damned touchy about permissions on floppies it hasn't made/formatted. They're still FAT-format!
 

GearTechWolf

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The saga continues! While the USB-floppy technically still works in of itself, it cannot read disks made by other drives and vice-versa.
So it's clearly out of alignment from running the cleaning-disk through it. Time to see what USB-floppy stuff the local computer place has...
 
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