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Osborne 1 Floppy disks?

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wheagy

Experienced Member
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Apr 10, 2010
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101
Hi,

I have an Osborne 1 that I've been working on for the last few weeks (single density...no DD mod). I don't have Osborne floppies, so thought I'd install a Gotek and once that works, I can make my own floppies. Several weeks later and I finally have a working Gotek from which the Osborne can boot. However, I cannot seem to get either of the floppy drives to work. I've tried both as a B drive with Gotek as A (I did remove the header on the original A drive to use it as B). The one drive does not seems to move the read/write head along the disk in both directions (it only moves to reset and does not move the other direction - it has been cleaned and I can move it by hand). The other moves the head as expected but when I format a disk, it simply prints EEEEEEEEEEEEEEEEE, which I'm guessing means Error?

I'm also not sure about what kind of disks to use? From what I could find, I need a single sided, single density, soft sector floppy? Is that correct? I found a few of these and they all behave the same way in the drive. It's possible that the floppies are all bad, but I feel it's more likely that the drives are bad and/or I'm using the wrong kinds of floppy disks.

Any ideas?

Thanks,

Win
 
Most 5.25 floppies are soft-sector; otherwise the manufacturer's label will state otherwise. Another point to consider is that you need to use low/double density (DD) and not high-density (HD) floppies. From a medium standpoint, there's no difference between single- and double-density. That distinction lies in the floppy controller.
 
Most format programs actually do something, and then verify. If the disk is giving any sort of problem, you would see that the drive is attempting to do something, even if just write one track, before it detects an error. your description suggests something to do with the actual drive. Is the disk spinning?

The vast majority (as in 99%) of my floppy disks of various mfg, and lots of no-name ones, are all working perfectly, so it's unlikely to be the disks. As Chuck suggests though the drive may not take kindly to ant HD disks, as the magnetic characteristics are not correct.

geoff
 
Yes, I am using several different floppies, some of which are specifically labeled SD and others that are DD. They all do the same thing. Yes, the drive is spinning. I also swapped the electronics between the two drives in case one was bad, but it made no difference. Only one drive has the head moving back and forth freely. I've been focusing on that drive, but have had no luck. When I start the format, the head moves rapidly back and forth on the disk one time and writes EEEEEEEEEEE... That all happens in about 2 seconds and then the drive stops and it asks about formatting another disk, so I'm pretty sure it's not actually doing anything. If I try a sysgen, It gives me a "write failed" or failure message (something like that) for drive B.

Win
 
Sounds like both drives are not working correctly or there's other issues with your system. Did you buy a new ribbon cable or is this the original cable? Are you trying to use one or both drives at the same time? Did you change the drive select jumpers for 0 & 1 (or 1 & 2) depending on the brand drives? Both can't be drive one.

The diskettes are all double sided when made. The OEM often just tested one side and sold them as single sided. Ditto on SD or DD too The drive is either 48 tracks per inch or 96 tracks per inch and share the same diskettes. PC's floppy drives mostly on the other hand use HD diskettes and have different needs. So stick with SD or DD diskettes. But that's not your problem when the heads don't move! A working disk drive when formatting a diskette may format the whole disk and then verify it or it might verify as it progresses. Depends on the program, I guess. So you should see the heads making 48 steps as it formats. Have you attempted to clean the heads? If caked up with junk from old defective diskettes you'll never get a good diskette made.
 
Don,

I'm only using one floppy drive at a time. The Gotek is A and the floppy is B. Both floppy drives are jumpered for B at the moment. I did not try a new ribbon cable, so that is something to check, but it works with the Gotek, but I suppose something could be hosed for the B drive.

I cleaned the heads on both drives as well as lightly lubricated the rails and stepper screws and both of them are pretty clean overall. I can move both drives heads easily by hand, but one of them under Osborne control only moves to the reset position and doesn't move back the other way. The other drive moves both directions on its own. But that drive, when I do a format, moves fully across the disk and back to reset in like 2 seconds (that's when the format software writes EEEEEEEEE to the screen). So it's happening way too fast. I've been focusing on that drive and swapped the electronics from the other drive as a test and that made no difference.

I was hoping to cobble together one good floppy drive to use with the Gotek, but worst case I can just use the Gotek. But these drives look so clean it seems like they should be working.
 
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Does your floppy cable have a twist in it, between the first and last connector?

I would have thought that an older machine of this type would require the two drives to be normally jumpered as A: and B:, so the cable would be flat with no twist. As I understand it, the twist is because later on in the history of PCs, all drives were supplied (I think) as B:, many did not even have jumpers, and the twist faked the one after the twist into being A:. So, if there IS a twist, then both drives should be jumpered as B:, but the one required to be A: should be connected after the twist, i.e. furthest from the motherboard.

Or have I got that the wrong way around?

Geoff
 
If you want to test the drives out of the Osborne there's a couple of devices that does that using a PC (I guess Apple too?). I bought a Supercard Pro and have been using it to test some old drives I had here. It allows you to test for read/write, speed and formatting plus head track movements. Plus you can backup a complete flux copy of a diskette and make copies. Works for 3.5 and 5.25 drives and can work for 8" and HDD's too per their website forum.
 
There is no twist in the cable. By the looks of things, I'm pretty sure it's the original cable. I don't think I have another cable like this one (my cables all have the twist) but I'll see if I can cobble something together and rule the cable out as a problem. As it is, I have a Gotek and printed the 5.25" tray holder for it. I think I'll put it back together with the Gotek in place of the A drive and one of the non-working drives in for the B drive. Obviously the Gotek makes the Osborne very usable. I may get more time to mess with this again in the future. I saw the post about the Supercard Pro...that sounds interesting and might be a future project.

Thanks for the help.

Win
 
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