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1.4 floppy drive read issue
- Thread starter mori512k
- Start date
Thats normal if the drive cannot see track 0, or the disk isnt formatted.
It's possible the spring holding the heads together isn't doing its job. If you can use it while it's outside the machine, try gently pushing down on the upper head with your finger. if it reads successfully, then that's the problem, and the fix is fairly simple: remove the head and readjust the spring.
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thats dangerous, as you can knock out the cylinder alignment and then you got an issue.
Track alignment is easy as rotating the stepper motor. Cylinder alignment.. not so much....
One thing you can do, is reformat the disk with the same drive. If it formats successfully, even after a couple attempts, but cannot be read by another drive the track alignment is off. That can be fixed by the method I spoke of just above.
Track alignment is easy as rotating the stepper motor. Cylinder alignment.. not so much....
One thing you can do, is reformat the disk with the same drive. If it formats successfully, even after a couple attempts, but cannot be read by another drive the track alignment is off. That can be fixed by the method I spoke of just above.
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As far as I'm aware from my messing around with floppy drives, the seek to track 0 has no dependency on the contents of the floppy data, or whether the disk is formatted. It's just a sensor of some kind that detects when the R/W head has reached its travel limit.
What does the Mac report when this happens? Is there any kind of error message or error code? I assume you're talking about inserting the disk when it's sitting at the bootup screen with the flashing question mark? Does it then show the disk icon with an X on it?
What does the Mac report when this happens? Is there any kind of error message or error code? I assume you're talking about inserting the disk when it's sitting at the bootup screen with the flashing question mark? Does it then show the disk icon with an X on it?
The head moves to the center because it's reading track 0, where it reads a few sectors to check if a disk is bootable. So that's normal. It's also normal to eject the disk if it thinks it's not bootable.
Sounds like your internal floppy drive probably just needs to be disassembled, cleaned, and lubricated. This is a very common problem with older floppy drives, and fixing it isn't difficult.
https://wiki.68kmla.org/Floppy_drive_lubrication
https://wiki.68kmla.org/Floppy_drive_lubrication
The Stepper motor on the back, has a retaining ring and set-screw, if you loosen the screw, lock ring, the motor will "physically turn" This adjusts track alignment.
You adjust this stepper motor as a LAST RESORT, and it should be done with the assistance of a scope and a properly formatted aligned floppy diskette.
You adjust the stepper motor until the analog waveform from the pickup heads is at its maximum amplitude. Careful, you dont wanna jump tracks! You need a high impedance probe, as the loading can cause problems. But your still looking for maximum amplitude of the pickup signal. If a lower impedence scope is the only thing you have, you could possibly tap into the signal on the output of the head amplifier. where that is on that drive I dont know.
Floppy drives that read, but do not write or fail to format (rare) is caused by a lack of BIAS drive.
your supposed to have a special floppy diskette that is recorded with a specific signal, so you can pick up signal distortions, and other types of motor flutter and head wear. But eh, we can wing it without it.
You adjust this stepper motor as a LAST RESORT, and it should be done with the assistance of a scope and a properly formatted aligned floppy diskette.
You adjust the stepper motor until the analog waveform from the pickup heads is at its maximum amplitude. Careful, you dont wanna jump tracks! You need a high impedance probe, as the loading can cause problems. But your still looking for maximum amplitude of the pickup signal. If a lower impedence scope is the only thing you have, you could possibly tap into the signal on the output of the head amplifier. where that is on that drive I dont know.
Floppy drives that read, but do not write or fail to format (rare) is caused by a lack of BIAS drive.
your supposed to have a special floppy diskette that is recorded with a specific signal, so you can pick up signal distortions, and other types of motor flutter and head wear. But eh, we can wing it without it.
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You can wing it without one but it will take finesse to bring it in.
You cant really screw it up if it doesnt work anyway, so why not?
You cant really screw it up if it doesnt work anyway, so why not?
I know that it can cause cylinder misalignment, but I've had good luck with tightening that spring that holds the heads together. It's like they're not contacting the disk like they should, and can't read or write properly, and doing this fixes it.
That's not to say it's the only problem, but it seems to be a fairly common one in my experience.
Also, I've turned the stepper motors a bunch, and it never seems to do anything to the alignment (a drive with a completely messed with stepper motor will read disks just as well as it did before the motor was messed with). This could simply be good luck on my part, though. Don't know...
Anyway, hopefully you can get that drive going again.
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That's not to say it's the only problem, but it seems to be a fairly common one in my experience.
Also, I've turned the stepper motors a bunch, and it never seems to do anything to the alignment (a drive with a completely messed with stepper motor will read disks just as well as it did before the motor was messed with). This could simply be good luck on my part, though. Don't know...
Anyway, hopefully you can get that drive going again.
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I sorta power read so I may have missed it. But are the heads touching when manually injected without a floppy? One issue I had was when cleaning I would gently pull up on the upper head. This pulls out a ribbon that can get pinched, causing the upper head not to seat all the way down when media was injected. It very easy to do and overlook.
Just a shot in the dark.
Just a shot in the dark.
