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Disk drive adjustments, floppies not compatible between drives...


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I have 3 drives, all 3 drives have speed set to 199.8ms-200.2ms via the Copy ][ Plus program.


Floppies formatted in drive A work fine in drive A, disks formatted in drives B and C work fine in drives B and C. Are there any other adjustments to make to bring drive A in family with drives B and C?




I had earlier asked for advice on programs that could test floppy disks and got some suggestions (http://atariage.com/forums/topic/262456-any-floppy-disk-check-programs/).


A bit of history. The three drives mentioned above when I first started working on these:

A: Apple Disk ][ with Drive 1 sticker (made lots of noise, didn't seem to read any floppies)

B: Micro SCI with Drive 2 sticker (seemed to work fine)

C Apple Disk ][ without drive sticker (only seemed to spin the disk)


I started using ADTPro and created a few disks using the drive A. Those disks worked fine in drive A only. All existing floppies only seemed to work in drive B.


Then, I was an idiot and somehow managed to break both drives A and B. After looking around, it seemed I needed new 74LS125 chips. A few days later and a dozen new 74LS125s, I actually got all 3 drives working. Turns out, drive C had a bad chip as well, in fact, when I removed it from the socket, the bottom of the chip fell off. It was well and truly smoked!


So, will all 3 drives working and the heads fully cleaned, I used Copy ][ Plus to check things out. I got all 3 drives dialed in to 200.0ms as close as I could. Drives B and C seem to be 100% compatible and seem to read old floppies and new floppies written on drives B and C just fine. Drive A works only with disks written on drive A.


Are there any other adjustments other than drive speed that I can adjust to get drive A working?

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You should take a look at speedyG's Disk II webpages.

It shows all the possible tuning you can achieved.


It seems your drive A has a misaligned head. This kind of setting is tricky.


This seems like the most reasonable explanation....


I use Copy ][ Plus to check and then change my Drive Speed, if needed...



Edited by MarkO
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