This sounds like a great opportunity for a RUclips collab! Usagi and Curious marc just went through a bunch of work on floppy drives. I bet that they can point you to whatever resources you need to go as deep down the rabbit hole as needed. Scoping out the buffered signals coming off the heads might give you the true picture of what is happening. I admit ignorance on most disk drives.
The optical encoder was used to check drive speeds using a fluro lamp ... when the pattern was stationary at the correct mains frequency the drive was running at the correct speed. IIRC the spindle was belt driven so this was important for detecting belt slip. Wrong speed -> disk won't read.
I replied to a couple comments but adding a few extra details... Before adjusting or disassembling drives, exhaust all other possibilities if you can. Like the guy that mentioned RAM issues, or a bad cable, or a cable on the drives has come loose. Be thorough inspecting and trying the easy stuff first. Can you find an Osborne person in your area you can meet with to check your disks. Best way to alleviate that variable so you know it is not the disks you bought. But again, I would not assume the disks are bad right away.
I think she's dead now but this woman had a (maybe linux) program that would format and write to disks in any format you want, she once found a bug in windows, patched it in assembler and sent her patch to MS, she got a cease and desist letter in return "do not modify our software"
BOOT ERROR suggests it is reading sectors but cant find anything it recognises as a boot program ... some machines of that vintage used an alternate sector mark or checksum to indicate the track was bootable ... I don't know if the Osborne was one of those, it is all too long ago.
The drives definitely are trying to read the disks. I don't think the drives are really bad. It looks more like either the disks are bad, or the head alignment is off. Most likely the latter, and maybe the disks are a bit wonky as well. I'd try to find a manual to align the head and then go from there.
I bought the disks from an eBay seller who seems to specialize in selling copies of Osborne software, so I'm guessing those are relatively fresh. That suggests alignment issues.
@@Lantertronics Yep. I remember WAAAAAYYYYYY back in the mid 80's when I hand(!) aligned Apple II disk drives. Yes, that was absolutely possible back then, because the tracks were as wide as a railroad track. ;) Well, almost. :D Edit: You might also want to check the speed of the rotation. That's where the little disks at the bottom of the rotor wheel come in handy. Shine a 60Hz light on them (old light bulbs) and the pattern on the outside should be static. If not, you need to align the speed.
Boot errors on the Osborne don’t necessarily indicate problems with the drives or disks. The boot up screen only uses the first bank of RAM, but loading from disk uses the other three banks of RAM. So if you have any bad RAM chips in those banks, you just get boot errors. It’s very likely one of those RAM chips has failed. I wrote up my experience of diagnosing and fixing this on one of my Osbornes here: github.com/richardloxley/Z80DecoderOsborne1
We did have two instances where it said it was trying to load CP/M -- do you think that still suggests bad RAM? Maybe in those a few cases we lucked out and the RAM chips worked for a bit and then glitched?
Are any of the disks a DOS boot disc? I Just remembered that C/PM worked on DOS machines in later versions, but I would try DOS. I'm not convinced it's the drives. 10:49 that's record/playback head chatter. Not a good sign, could be the disc itself has physical damage, because the head is trying to find any data it can read. The bad sector error makes that much more likely, as the drive has given up on it's task without reading any data.
According to the eBay seller all 5 should be bootable. We did get a couple of instances where it looked like it was trying to load CP/M but then got BDOS errors (at 4:00 and 8:15).
As an audio engineer, my first thought is unseen physical damage. the disc is essentially magnetic tape, which is essentially just scotch tape and rust, and after a while the playback/rec head starts wearing the rust off the tape, and eventually that's a problem. Same thing happened to Steely Dan while recording "Kid Charlemagne" as they recorded more and more takes so many times the master started losing tracks.
@@shipofthesun It's possible that there was gunk on the heads before I tried cleaning the heads that messed up the disks, and now the disks are messed up and can't be read now that I've cleaned the heads.
No, so right now the drive that's labeled "A" in red is actually being interpreted as the B: drive and the drive that's labeled "B" in red is actually being interpreted as the A: drive.
@@Lantertronics The resistor pack is just a termination resistor. It must always be installed on the drive at the end of the ribbon cable. It does not determine which drive is A or B. That is either determined by a jumper on the drive, or by a twist on some of the wires on the ribbon cable (where the select wires are reversed for A vs. B). IBM PC's often used a twist. I believe TRS-80's used a jumper. The drive should have a jumper regardless. I didn't see a twist on your Osborne, so it is probably a jumper on the drive. I don't have my Osbornes handle right now (I have several). Otherwise, I could check. If you get desperate, I can pull one out of storage and see.
@@mglohmeyer OOOOOOH!!!! Now that is a VERY important detail. First thing I will check when I get back in is where the termination resistor pack is. I may have it in the wrong place.
The heads should be able to move much more freely than that. It should be doing this when failing to boot ruclips.net/video/Tu5KvC9L3uE/видео.html I'd put a drop of light machine oil on the sled and actuator mechanism. Cheers.
@@Lantertronics FYI, the head motor is a stepper motor. There is no servo mechanism here. Saying this to point out that alignment is a whole system alignment, and once aligned, track to track alignment is determined by the stepper motor step distance, so no track to track alignment is needed. So alignment is actually pretty simple, but.... I would not suggest messing with alignment until you have exhausted all other avenues such as cleaning the disk heads, making sure the spindle speed is correct using a 60Hz light on the paper disk with the dashes where it says 60 (Hz) and 50 (Hz), and making sure the drives are connected correctly. Once you touch alignment, you might make it worse without the proper tools. Other people who have aligned drives before can hopefully explain better. Said another way, don't start adjusting or disassembling things first. Do that last. Also, make sure the rails/slides or bearings involved in the head movement are clean and not clogged up with old grease, dirt, etc. I am mostly familiar with IBM PC and TRS-80 floppy drives, which have chrome rails for the head mechanism to slide on, and I have gotten read issues to go away by cleaning these rails, and (maybe) lightly oiling them - check service manual about oiling, or get help from someone that knows drive repair before just oiling stuff. The Osborne drive looks like it has a worm drive shaft, and that might be dirty and need a bit of grease or maybe the grease on the stepper motor bearings is old and dry, causing it to not move correctly. Remember, oil and grease can go everywhere, so know if is needed, don't just assume. Otherwise, you will get grease on your floppies. The point I am getting at is, alignment shouldn't go out just due to age, but grease and belts can definitely go bad with time causing speed and alignment issues. Alignment would go out due to usage or being dropped (which could have happened too). I'll say more in reply to some other comments.
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This sounds like a great opportunity for a RUclips collab! Usagi and Curious marc just went through a bunch of work on floppy drives. I bet that they can point you to whatever resources you need to go as deep down the rabbit hole as needed. Scoping out the buffered signals coming off the heads might give you the true picture of what is happening. I admit ignorance on most disk drives.
The optical encoder was used to check drive speeds using a fluro lamp ... when the pattern was stationary at the correct mains frequency the drive was running at the correct speed. IIRC the spindle was belt driven so this was important for detecting belt slip. Wrong speed -> disk won't read.
Ah, that's good to know. The lights in my office on campus are fluorescent so that should work.
an Osborne eh? I heard the next model was going to be better so I'm waiting for that one. 😅
Funny thing: my son asked me if there was an Osborne 2, so I got to tell him the story about the Osborne Effect.
I replied to a couple comments but adding a few extra details...
Before adjusting or disassembling drives, exhaust all other possibilities if you can. Like the guy that mentioned RAM issues, or a bad cable, or a cable on the drives has come loose. Be thorough inspecting and trying the easy stuff first.
Can you find an Osborne person in your area you can meet with to check your disks. Best way to alleviate that variable so you know it is not the disks you bought. But again, I would not assume the disks are bad right away.
I think she's dead now but this woman had a (maybe linux) program that would format and write to disks in any format you want, she once found a bug in windows, patched it in assembler and sent her patch to MS, she got a cease and desist letter in return "do not modify our software"
BOOT ERROR suggests it is reading sectors but cant find anything it recognises as a boot program ... some machines of that vintage used an alternate sector mark or checksum to indicate the track was bootable ... I don't know if the Osborne was one of those, it is all too long ago.
The drives definitely are trying to read the disks. I don't think the drives are really bad. It looks more like either the disks are bad, or the head alignment is off. Most likely the latter, and maybe the disks are a bit wonky as well. I'd try to find a manual to align the head and then go from there.
I bought the disks from an eBay seller who seems to specialize in selling copies of Osborne software, so I'm guessing those are relatively fresh. That suggests alignment issues.
@@Lantertronics Yep. I remember WAAAAAYYYYYY back in the mid 80's when I hand(!) aligned Apple II disk drives. Yes, that was absolutely possible back then, because the tracks were as wide as a railroad track. ;) Well, almost. :D
Edit: You might also want to check the speed of the rotation. That's where the little disks at the bottom of the rotor wheel come in handy. Shine a 60Hz light on them (old light bulbs) and the pattern on the outside should be static. If not, you need to align the speed.
Boot errors on the Osborne don’t necessarily indicate problems with the drives or disks. The boot up screen only uses the first bank of RAM, but loading from disk uses the other three banks of RAM. So if you have any bad RAM chips in those banks, you just get boot errors.
It’s very likely one of those RAM chips has failed.
I wrote up my experience of diagnosing and fixing this on one of my Osbornes here: github.com/richardloxley/Z80DecoderOsborne1
Ooooooh! That's very good to know!
We did have two instances where it said it was trying to load CP/M -- do you think that still suggests bad RAM? Maybe in those a few cases we lucked out and the RAM chips worked for a bit and then glitched?
Are any of the disks a DOS boot disc? I Just remembered that C/PM worked on DOS machines in later versions, but I would try DOS. I'm not convinced it's the drives.
10:49 that's record/playback head chatter. Not a good sign, could be the disc itself has physical damage, because the head is trying to find any data it can read. The bad sector error makes that much more likely, as the drive has given up on it's task without reading any data.
According to the eBay seller all 5 should be bootable. We did get a couple of instances where it looked like it was trying to load CP/M but then got BDOS errors (at 4:00 and 8:15).
@@Lantertronics I updated the post, and it smells like disc errors rather than hardware.
As an audio engineer, my first thought is unseen physical damage. the disc is essentially magnetic tape, which is essentially just scotch tape and rust, and after a while the playback/rec head starts wearing the rust off the tape, and eventually that's a problem. Same thing happened to Steely Dan while recording "Kid Charlemagne" as they recorded more and more takes so many times the master started losing tracks.
@@shipofthesun It's possible that there was gunk on the heads before I tried cleaning the heads that messed up the disks, and now the disks are messed up and can't be read now that I've cleaned the heads.
@@Lantertronics You might be right. I'm on the edge of my seat for the next installment.
Drive A looks like it is booting .. ignore the different sounds as they varied widely.
DId you put the cabling and resistor pack back the way it started?
No, so right now the drive that's labeled "A" in red is actually being interpreted as the B: drive and the drive that's labeled "B" in red is actually being interpreted as the A: drive.
@@Lantertronics The resistor pack is just a termination resistor. It must always be installed on the drive at the end of the ribbon cable. It does not determine which drive is A or B. That is either determined by a jumper on the drive, or by a twist on some of the wires on the ribbon cable (where the select wires are reversed for A vs. B). IBM PC's often used a twist. I believe TRS-80's used a jumper. The drive should have a jumper regardless.
I didn't see a twist on your Osborne, so it is probably a jumper on the drive. I don't have my Osbornes handle right now (I have several). Otherwise, I could check. If you get desperate, I can pull one out of storage and see.
@@mglohmeyer OOOOOOH!!!! Now that is a VERY important detail. First thing I will check when I get back in is where the termination resistor pack is. I may have it in the wrong place.
The heads should be able to move much more freely than that. It should be doing this when failing to boot ruclips.net/video/Tu5KvC9L3uE/видео.html
I'd put a drop of light machine oil on the sled and actuator mechanism. Cheers.
What alignment system do they use? Is it a head to track alignment issue?
That's a good question. I have docs for it and will investigate.
@@Lantertronics FYI, the head motor is a stepper motor. There is no servo mechanism here. Saying this to point out that alignment is a whole system alignment, and once aligned, track to track alignment is determined by the stepper motor step distance, so no track to track alignment is needed. So alignment is actually pretty simple, but....
I would not suggest messing with alignment until you have exhausted all other avenues such as cleaning the disk heads, making sure the spindle speed is correct using a 60Hz light on the paper disk with the dashes where it says 60 (Hz) and 50 (Hz), and making sure the drives are connected correctly. Once you touch alignment, you might make it worse without the proper tools. Other people who have aligned drives before can hopefully explain better. Said another way, don't start adjusting or disassembling things first. Do that last.
Also, make sure the rails/slides or bearings involved in the head movement are clean and not clogged up with old grease, dirt, etc. I am mostly familiar with IBM PC and TRS-80 floppy drives, which have chrome rails for the head mechanism to slide on, and I have gotten read issues to go away by cleaning these rails, and (maybe) lightly oiling them - check service manual about oiling, or get help from someone that knows drive repair before just oiling stuff.
The Osborne drive looks like it has a worm drive shaft, and that might be dirty and need a bit of grease or maybe the grease on the stepper motor bearings is old and dry, causing it to not move correctly. Remember, oil and grease can go everywhere, so know if is needed, don't just assume. Otherwise, you will get grease on your floppies.
The point I am getting at is, alignment shouldn't go out just due to age, but grease and belts can definitely go bad with time causing speed and alignment issues. Alignment would go out due to usage or being dropped (which could have happened too).
I'll say more in reply to some other comments.
@@mglohmeyer This is incredibly useful info! Thank you!