5.25 floppy drive writing issues

wbahnassi

New Member
Jan 5, 2020
2
0
1
Hi, I have a TEAC FD-55GFR 5.25" 1.2MB disk drive. It reads disks great (both DD and HD) under DOS 6.22. But if I use it to write even one byte on the disk, then the disk gets corrupted. Reading the disk results in "General read error". Trying to format it fails with "Invalid media or track 0 bad - disk unusable". Not even VGACopy can deal with the disk anymore. IMGDisk fails to write with error "NoAdrMark".

I've read that those TEAC drives are known to be some of the best, so I feel bad about throwing this one away if it can be fixed.

Problem is, what part of the disk machinery could result in such fails? A faulty write head?

Things I've tried:
* Reads disks perfectly of all formats
* IMGDISK alignment test succeeds 100%
* Cleaned heads and sensors (index & write protect)
* Connected another floppy drive, reads & writes perfectly, so it's not the controller or the motherboard

Procedure to fail:
* Insert a working disk in drive A:
* Do "dir", files are listed successfully
* Go to drive A: and write something, I use "Echo hi >> test.txt"
* Do "dir", files are listed correctly and new file shows up
* Do "type test.txt", it prints "hi"
* Do "dir", you get "General Read Error" from now and forever

So interestingly, the write seems to succeed at first but the disk gets corrupted a few seconds after writing is done.

Any idea on where to look for the problem?

Best
 

cml37

Moderator
Staff member
May 19, 2019
172
40
28
Washington, D.C. Area
Hi, I have a TEAC FD-55GFR 5.25" 1.2MB disk drive. It reads disks great (both DD and HD) under DOS 6.22. But if I use it to write even one byte on the disk, then the disk gets corrupted. Reading the disk results in "General read error". Trying to format it fails with "Invalid media or track 0 bad - disk unusable". Not even VGACopy can deal with the disk anymore. IMGDisk fails to write with error "NoAdrMark".

I've read that those TEAC drives are known to be some of the best, so I feel bad about throwing this one away if it can be fixed.

Problem is, what part of the disk machinery could result in such fails? A faulty write head?

Things I've tried:
* Reads disks perfectly of all formats
* IMGDISK alignment test succeeds 100%
* Cleaned heads and sensors (index & write protect)
* Connected another floppy drive, reads & writes perfectly, so it's not the controller or the motherboard

Procedure to fail:
* Insert a working disk in drive A:
* Do "dir", files are listed successfully
* Go to drive A: and write something, I use "Echo hi >> test.txt"
* Do "dir", files are listed correctly and new file shows up
* Do "type test.txt", it prints "hi"
* Do "dir", you get "General Read Error" from now and forever

So interestingly, the write seems to succeed at first but the disk gets corrupted a few seconds after writing is done.

Any idea on where to look for the problem?

Best
Could it be a disk controller issue? Have you tried the drive in another system?
 

wbahnassi

New Member
Jan 5, 2020
2
0
1
I haven't tried it on another machine. Unfortunately I have only one floppy-capable PC. However, I have another 3.5" 1.44MB drive. If I connect the 3.5" floppy drive instead of the 5.25" then the 3.5" drive is able to read and write successfully without trouble.
I don't think this completely rules out the disk controller but it's an indicator that it's probably not the disk controller. Of course I make sure that the BIOS is configured correctly for each case (5.25" 1.2MB vs 3.5" 1.44MB).

In the mean time I'm gonna have to find someone in my area who has a floppy-capable PC so I can try the drive on his computer instead of mine. I'm in Montreal Canada, so if anyone is close by let me know 😊

So yeah, any suggestions are still welcome.