Connecting a Mini Disk Drive to a CoCo FD501 interface

[tastypies]

I have a Mini Disk Drive (26-1160B) but no ribbon cable...

The Mini Disk Service Manual (71013-001) has a section on Flat Ribbon Cable Assembly (page 27), which suggests that for drive 0
pins 12, 14, and 32 need to be removed when connecting the drive to an Expansion Interface.

Do these same pins also need to be removed when connecting this drive to a CoCo FD501 interface?

 

[TRS-Ian]

Yes it's the same cable.

 

[Eudimorphodon]

Back in the dark ages shortly after I bought my Model I at a garage sale in the early 1990's I got it into my head to upgrade my disk drive boxes to double-sided drives pulled from the IBM 5150s the government surplus places were dumping for sub-$50 each. In the process I ended up de-Tandy-fying the remaining single-sided drives so they used standard drive select jumpering instead of the "missing teeth" schema so I could mix them freely on the solid cables I needed for head select to work. I guess doing that modification today on an original equipment drive might not be kosher, but if you ever want to go to a third-party DOS or use OS 9 to support double-sided drives you may need to do the same. (Or just not use the original drive in the harness.)

(Without looking I'm not even sure how easy it would be, since all my drives were third party and not original Radio Shack. I remember a few that just needed a custom jumper block pulled out but there was another brand one that was hacked with cut traces and jumpers, ended up consigning that one to the junk pile.)

 

[tastypies]

So....I now have a cable as per the spec (with pins 12, 14 and 32 removed), and connected the drive to the FD501 CoCo interface.

However, when try to format a blank disk using DSKINI0, the drive spins for a while and then stops with an ?IO ERROR. The same happens when try DIR, it whirs, then stops with an i/o error. With either command there is a faint stepping noise, suggesting it is trying to do something.

I’d be grateful for any suggestions on narrowing down the problem. Is it the FD501, my cable, the drive, or the floppy disks (48tpi ds)? My own guess is that the problem is with the drive, as when I opened it, it was pretty dusty, with a couple of dead spiders thrown in free.

Thanks.

 

[tastypies]

It's alive..!

It's alive..!

My own guess is that the problem is with the drive, as when I opened it, it was pretty dusty, with a couple of dead spiders thrown in free.

Decided to completely disassemble the drive:



The good news is that after cleaning the head with isopropyl alcohol and putting the unit back together, everything seems to be working:



YAY...! :D