Initially I had a similar issue as the M68 - "ROTATION SPEED ERROR" whatever that means. I had a couple of FD-50C-11 drives that I picked up from a recycling place, so thought I'd try hooking one of those up to the test rig I made to image the M68 HD disk, and surprisingly it images without error, and viewing the image I could see Sord copyright notices etc in there so even though SSQD isn't anything a PC knows about, the drive worked.
That's where the similarity with the M68 stopped. In that case, I had read errors because of a dodgy drive but could list the directory, and Jeff sorted out the image so I could use it as a copy destination. On the M23, I cannot read the disk - I get DISK FAIL when trying to list the directory, and it will not boot off the disk - it doesn't even try, with "RA" flicking but no other activity.
I'm wondering if this would be something that's related more to interfacing? When trying to init the disk, it steps rapidly up and down the track numbers but fails on every track, but it doesn't even seem to try when trying to list the directory or boot. The jumpers set on the FD-50C are HM, MX and one of the DS lines. This particular drive (100tpi) seems reasonably uncommon, but it looks like the TRS-80 used the 50A 48 tpi version so I'm hoping there's some more info out there. The spec sheet for this drive has a note saying that pin 2 is head load, 6 is ready and 34 is drive select 3; I wonder if those are non-standard settings?
Looking forward to any guidance! I've attached the image made on the PC, and put service info I found for the FD-50 here - https://1drv.ms/b/s!Ajyp8sRoAWZanp9hJXS ... w?e=BjE5sF (it's too large to attach).
Thanks
