IIRC, you mentioned that the other drive works, and you were able to boot DOS? If so, setup the faulty drive as drive B:, boot DOS, and try formatting a blank disk in the B: drive - if it works and you can read/write files to the drive, the it is probably just a little out of alignment (You will probably find that the disks it makes cannot be accessed on other drives). Assuming this doesn't work, what error message does DOS give whwn trying to access the drive? Also, normally the system will try much longer to access the drive if it is seeing sector pulses - if it behaves pretty much the same with the diskette in as with it out, then you may have an index sensor problem. With power off, manually move the head out some distance from track-0 - does it step back when the system starts - does it perform the "Seek test" at power- up and does it look and sound exactly like the other drive? - if no to any of these, perhaps there is a problem in stepping/track select, track-0 sensor. Also, "scopes are your friend" - of you have one, take a look at what is going on at the interface when you try and access the drive - you should see the select line go low, look for index pulese, step pulses, track-0 detect, data I assume you have already done this, but clean the head, and check all connectors for even a little corrosion (edge, head, steppers etc.), especially if it has been sitting around for a long time - same goes for config jumpers and option blocks A good cleaning often does wonders! Regards, Dave -- dave04a (at) Dave Dunfield dunfield (dot) Firmware development services & tools: www.dunfield.com com Collector of vintage computing equipment: http://www.parse.com/~ddunfield/museum/index.html