First post, by nathana
Hello,
I recently purchased 2 "refurbished" (appear to be heavily used but somewhat cleaned up) 2.88MB Extended Density 3.5" floppy diskette drives. They are slimline model drives, originally packaged in an UltraBay carrier by IBM and intended for use with the ThinkPad 75x/76x line. (I was only in the market for one, but the price was so good I went ahead and purchased a spare to go with it.)
The particular ones I have are manufactured by Alps Electric, model DF328N101A.
I originally purchased these intending to try to get at least one of them to work in an old ThinkPad 770 I have, either by gutting a 1.44MB HD drive from its UltraBay II caddy and replacing it with this, or by putting it in a SelectaDock III after swapping out the UltraBay II slot option in the dock with the original dual-UltraBay I option from the SelectaDock II (they are interchangeable).
However, when I bought these, I also ran across some slimline floppy (26-pin, 1.0mm-pitch FPC) to standard desktop PC floppy (34-pin standard ribbon) adapters. If you free the drives from their UltraBay shells, you find that these are just standard slimline laptop floppy drives under-the-hood. And it was going to be easier to test these first on a desktop PC with those adapters, so that's what I did: tried hooking them up to a motherboard that has 2.88MB floppy support.
However, I can't get *either* drive to work. At this point, I've tried both drives on 3 different PCs, 3 different cables/adapters, and multiple different known-good diskettes.
The symptoms are 100% identical between the two drives: they power up just fine, they perform seek during POST just fine, BIOS does not throw out any floppy drive error codes, it spins diskettes just fine, and the heads seek just fine. But when I ask it to read a disk from DOS, I just get back "General failure". If I try to format a disk from DOS, I get back "Invalid media or Track 0 bad". If I try to boot from a DOS boot floppy, the BIOS tells me there is no boot sector on the diskette. This is even on regular 1.44MB HD media.
I have tried setting the BIOS to 1.44MB instead of 2.88 just to see if that would at least change anything about the drives' ability to read 3.5" HD diskettes, but they behave identically regardless of how BIOS is configured. If I replace either of these ED slimline drives with an HD slimline drive, that HD drive works just fine in the same context (using the exact same adapters/cables, connected to the exact same PC, and reading or booting off of the exact same diskettes).
I have cleaned the heads on both drives, but no change.
At this point, I am baffled. I suppose both drives could be defective, but in the exact same way? This makes me wonder if there is something obvious I'm missing, or if perhaps there is some special consideration that needs to be taken into account with these drives that you wouldn't have to deal with on a slimline HD floppy drive (perhaps the ED density select pin isn't being bridged by any of the adapters I've tried using? could that cause this? but wouldn't at least HD media be readable in this drive without that signal??)
Any ideas or further troubleshooting thoughts would be much appreciated!