I've recently got my IIe out of storage and cleaned up both drives. One works OK but the other appears to function, but does not write. It apparently formats OK, I can download a DSK file using ADTPro, which runs without any errors, but when I examine the disk it has the original contents before the format. Can the write process proceed and fail without any error messages? ADTPro is working OK on the aufio link, there is no problem there.
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Since the act of formatting a diskette is in itself a writing function, I'd say your drive is capable of writing.
Mind you, ADTPro's formatting routine is a rapid format and probably does not do any checking, although I could be wrong.
Can you actually create diskettes that work? Your post indicates that this is the case, I think.
Create a DOS 3.3 master disk, boot it and then try the command INIT HELLO with a blank diskette inserted. See if it formats the disk properly.
Also, it should be mentioned that you need to be using DOUBLE density disks, since HD disks will not work properly in these drives.
Why not SINGLE density diskettes?
I'm only using the drive 1 ribbon slot on the card in the Apple. With Drive 1 hooked up, works perfectly. I can format and ADTPro images to the disk. With Drive 2 hooked up, format and ADTPro transfers seem to work OK. but nothing is written. Looks like there is no checking on Format from the ADTPro menu? Disks are DS/DD, not HD and previously used (Dysan and Wabash). Some have track 0 scuffed and don't work, but I have a couple that look clean and work OK on Drive 1. It seems quite sensitive to disk quality. If I attempt to use a scuffed disk, it messes up the head on Drive 1 and I have to cottonbud / IPA it to get it to run on one of the good disks. This has been reported here before some years ago. Spindle speed checks out OK. I found that a LED bench light gives a clearer image that a filament lamp. Even though these are driven from a HF inverter they are driven with raw rectified mains power, and no thermal lag with LEDs.
Created a DOS 3.3 disk. INIT proceeds uneventful, no errors, but no writes. I checked the write signal through the 74LS125, it is OK, but no signal on pin 1 of the CA3146. Swapped the chip from the other drive and it is now working. Need a new chip. Don't you like it when they used to socket through hole stuff!
The magnetic media in "single" and "double" density floppy disks is the same.
Wabash disks are notoriously bad: the problem seems to be that they used a lubricant that turns to varnish over time (like soya oil). After this happens, the surface is too sticky for proper head travel and the head will rip the coating off the substrate. You should probably just throw them all out.
Thanks, this will explain the dirty head issue, and why the surface gets scuffed at track 0. I'll look for some new disks, not easy in the UK. The CA3146 is available from Langrex in the UK. I avoid ebay chips, I've had duds from there.
Many old diskettes have mould growing on them that also causes this exact problem of build up on the head and scratching of the media, and every subsequent disk inserted in the drive.
If I even suspect this is the case on an important diskette I want the data from (sometimes I'll take a cotton swab and wipe the diskette surface with a touch of water and see if there's any discolouration on the swab) I slit the jacket, carefully remove the "cookie" and wash it under warm water and mild dish soap. Then I blot it dry on a paper towel, carefully reinsert it into the jacket (carefully! If you kink or wrinkle the cookie, it's ruined). This usually buys me a few good reads without any issues.
I then immediately create a disk image of that diskette, clean the read / write head afterwards and then discard the disk in the trash.