Floppy disk drive does not work after burning Power Macintosh 7200

[Roberto]

I have a problem with the floppy drive .... I have many HD floppies and I would like to try to make a selection to understand which are still usable and which are not. I started to format them with a Power Macintosh 7200 ... all right ... some working floppy and some floppy with some bad sector, until I found a cursed floppy. Why will you say? Because after trying to format on this floppy disk my Power Macintosh gave me an error and from then on it was no longer able to complete a format (not even its floppy disks that I was able to format correctly before). More precisely, inserting a floppy that had previously formatted, it tells me that it does not recognize the floppy and asks me if I want to format (Mac, ProDos, Dos): I tried all three types but in the end it does not complete any type of formatting . I have two Power Macintosh 7200, so out of curiosity I tried to format floppies with this second mac, all right, it manages to format HD floppies at 1.44 Mb (those that I could no longer format with the other Mac), but at a certain point I inserted that damned floppy and it caused me exactly the same anomaly as the other Mac. Now I am with two Power Macintosh 7200s that are no longer able to complete a format. Some idea? I tried to clean the head but nothing ....

 

[dzog]

I know you mentioned you cleaned the head - but that's what I was going to suggest. How much cleaning have you attempted? The 'cursed floppy' is perhaps quite dirty, or the media is disintegrating. Try both cleaning the head manually with 99% iso and doing a number of passes with a cleaning floppy. 

 

[Roberto]

I know you mentioned you cleaned the head - but that's what I was going to suggest. How much cleaning have you attempted? The 'cursed floppy' is perhaps quite dirty, or the media is disintegrating. Try both cleaning the head manually with 99% iso and doing a number of passes with a cleaning floppy. 

I used isopropyl alcohol when I disassembled the drive for a more thorough cleaning but it never convinced me that this could be the cause of the problem. It looks like that damned disk brought the floppy drive head out of alignment. Generally this is possible, but only in the writing phase when a copy is being made from an image disc where the latter has been done bypassing the physical movement limits of the head. In fact, one should always check how the image copy of a disc was made (especially when we download files from the internet). But it is not my case since the burning software is native to the operating system and I do not make any copies from the disk image.