I have had similar issues and found that some BIOSes are rather particular about where drives A and B go. If you just have the 5.25" drive connected, have you tried connecting it to the other location on the ribbon cable?

Have you confirmed that the 3.5" drive works? This is to check for a defective diskette controller IC.

It is also possible that there is some malfunction on the 5.25" drive itself. I have one that I'd like to fix one day, but it is so much easier to buy another drive.

I gave that a go. All I get is a "general failure" with no attempts to seek. It will try to seek during the bootup test.I tried making it drive B in the BIOS. I never did able to confirm that the 3.5 drive works. The problem I have now is that I only have one connector for 3.5 and I'm using that for a CF reader that simulates IDE. I'm going to be ordering a molex to floppy adapter so that I can hook up the 3.5 and do some testing. I always had the thought that maybe the cable is expecting two drives and doesn't work with one drive. I have my doubts. But who knows.

And you could very well be right that it is the 5.25. Although this was listed as NOS, it doesn't mean that it's not faulty. Once I get the molex adapter, I will test. And I will probably return this floppy to the seller if it still does't work. I think he still has a few in stock.

Just to elaborate on what feipoa said, some 3.5/5.25 drives are hardwired for a specific drive letter which corresponds to whether it is before or after the twist in the ribbon cable, if there is no option to change it, it's likely that's the case.

IIRC if there's no jumper to switch, it's hardwired to B, which is before the twist.

Edit: rereading your OP I see you've already been playing with the jumper. Hmm. I'd still try the above anyway. Might as well.

Some photos would help. The drive itself could be configured for Shugart interface rather than PC.

Deunan wrote:

Some photos would help. The drive itself could be configured for Shugart interface rather than PC.

This is why I love these forums --- All the old and obscure knowledge. I have literally never heard of this before and now I'm reading about it.

Edit: Oh. SCSI! Didn't know the "S" had multiple meanings.

I have had the exact same issue in the past and still no solution either. Really interested in how this turns out. It would be awesome if jumper pics could be posted too. I had messed with them in the past and so much time has passed, I have no idea where to begin.

Thanks so much, Guys!

I will post the jumpers pics a little later. At the same time, I'm working with the seller to get an exchange or return.

I heard back from the seller. He said this "These drives do not work in DOS/Windows environment. Per the item description, they are used in Unix systems and some game systems" His description just said it doesn't work in Windows. I think he's a bit full of it. I can see the drive starting to seek for those couple seconds. I never heard of drives only working for Unix - especially when I type in A:, it does something. But maybe I'm wrong here. I will post the jumpers and return it.

No way that's true. I did have both the 3.5" and 5.25" working at one point. The issue I had at that time was that the 5.25" would not read either LD or HD disks (can't remember which, but think it was LD). I had both LD and HD disks to test and those were the results. What I further tried to do was get just the 5.25" drive to work alongside a Gotek floppy emulator as the 3.5" drive. In trying to get that to work, I messed with the jumpers to the point of no return. I did a lot of research at the time and it's just one of those things that I put aside for too long and would have to start over.

If you can take a pic or detail what the stock jumper settings are, I can test mine again to get back to at least the 3.5" + 5.25" (HD only) state that I did have working back then. I can then do more testing and maybe help you get at least to there.

Again, Shugart drive. It will not work in DOS, Windows, or any PC for that matter unless modded. Which can be as easy as rejumpering or might require soldering.
Might have READY or DSKCHG, or both, at wrong pins. Might lack the HD detection switch/LED barrier. Might be locked to 300 or 360 RPM.

I know this is mainly a PC forum and PCs are the most popular machines out there, but that does not mean every floppy drive is a PC one. Again, most can be modded either way but it might not be very easy.

As promised, attached is the picture. I had to reduce the picture as the original size was 3MB and the forum posting only allows 2MB. I am curious if Deunan thinks this is a Shugart drive. I found a manual online of not my exact model, but I think it's similar. Not sure if jumper settings can get this to work or not.

I saw this wiki on Vogons: https://www.vogonswiki.com/index.php/Teac_FD-55_series. If I'm reading this, mine is an "F type" and not supporting high density?

Yeah, that's a Shugart FDD, there's a pinout in this datasheet that confirms it: http://v1050.classiccmp.org/chipset/fd55.pdf

And a bit weird one too. See that jumper below that shiny black box? It's set to RY, which means the pin 34 is /READY and not /DSKCHG like PCs expect. That would be the DC jumper position but the pin is missing so jumper or not, can't be easily changed. This is the why you get that short spin and then an error, a /DSKCHG should go away after a seek and /READY does not, obviously.

It would work if connected as B drive (so, before the twist in the cable) since then both drive select 1 and motor on match the PC signals. But even if you rejumper it to DC, it will probably confuse the hell out of the FDD controller since it can't do HD as you noticed - and the photo is a bit short but I think I found the ebay listing and you can see there is no LED or switch on the right side of the drive. There's only one near the spindle (first sector detection) and one for write protect on the left. And again the doc confirms it.

It might just be possible to use it as 360k PC drive. Doc says 320k but it is quad-capabe so I think it will work with 9 sectors per track just fine. But it can do 80 tracks unlike a typical 360k drive so there are various DOS tools for weird floppy formats and you could maybe use that to get 640k or 720k out of it. I'm not sure it's worth the trouble though.

Thanks for confirming. You are probably seeing the same listing as I indeed bought from eBay. Originally the listing said not compatible with Windows and I didn’t see that as a big deal since I was using this for DOS. But I have saw that since I contacted the seller, the description now says not compatible for windows or dos.

I am worried about making the same mistake. I’m looking at a Cannon MD 5501. Can you give me any tips on making sure it’s not a Shugart FDD

There are quite a few Mitsumi D509V3 drives on eBay which have beige bezels. I have a few of these drives and can say that they work with 1.2 MB diskettes in DOS and Windows.

E.g. https://www.ebay.com/itm/153406904848

I have bought one of these from this seller before, although they are listed as "as-is, no returns", the seller claims he/she has them tested before shipment. Mine even shipped with a faux floppy disk (cardboard insert) for some sort of head protective purpose during shipment. Keep in mind, though, that these bezels also came in tan. I have ordered other items from that seller, e.g. CD-ROM drives, which came defective, but were repairable, so, you might want to pay more from a seller who sells the D509V3 as "working" with warranty.

I have a Panasonic JU-475-5 AKO drive which is 5.25" as well. I have never been able to get it working. I no longer recall where it came from. I've attached some photos of it. Jumpered wrong? Should it be able to work in DOS/Windows, or does it suffer the same fate as the other poster's drive?

I have a post-it note on the drive which says:

1Defective
2-Disk I/O error
3-General Read Failure
4-Cannot read sector

Huh, weird that it has DS1-DS4 selection, not DS0-DS3. But in this case DS2 is correct setting for B drive, and probably won't work otherwise anyway - having 4 selections mean it's a Shugart too. It's set to DC so might just work, try it as a 360k drive as it seems not to have HD mode either but I can't tell for sure. If it doesn't work I'd have to look up the rest of the jumpers.

Thank you for your response.

I have always tried to set this drive up as drive B. Unfortunately, I only have 1.2 Mb diskettes.