Brendan
Experienced Member
I had recently picked up an Osborne 1A in pretty good shape from the local Austin, Texas, Goodwill Computer Works for $40.
After fumbling about trying to image disks in my very limited spare time (I don't have a dedicated DOS box for imaging single density floppies, although have been successful with DD under Linux) I picked up some Osborne 1A CP/M disks from eBay.
These proved to be unreliable. It seemed like they might boot once or twice and then not work until the system was shut down and sat for awhile. At the eBay seller's suggestion, I gave in today and opened up the case, pulled out the floppy drives and discovered that the spindle motors simply weren't spinning at the right rate (using the 60Hz strobe markings) on either drive. After adjusting the trim-pots, the system is working great and I was able to boot, use, and backup all the floppies.
To most of you hackers, this probably seems like part of an ordinary day, but for me, it was a small victory. :D
On another note, this is the first time I recall seeing drives that used a stepper motor driving a worm gear to position the head. Is this common, and I just never noticed it before? These drives carry a Siemens sticker.
After fumbling about trying to image disks in my very limited spare time (I don't have a dedicated DOS box for imaging single density floppies, although have been successful with DD under Linux) I picked up some Osborne 1A CP/M disks from eBay.
These proved to be unreliable. It seemed like they might boot once or twice and then not work until the system was shut down and sat for awhile. At the eBay seller's suggestion, I gave in today and opened up the case, pulled out the floppy drives and discovered that the spindle motors simply weren't spinning at the right rate (using the 60Hz strobe markings) on either drive. After adjusting the trim-pots, the system is working great and I was able to boot, use, and backup all the floppies.
To most of you hackers, this probably seems like part of an ordinary day, but for me, it was a small victory. :D
On another note, this is the first time I recall seeing drives that used a stepper motor driving a worm gear to position the head. Is this common, and I just never noticed it before? These drives carry a Siemens sticker.
