3.5" floppy drive question(s)

Curtis H. Wilbar Jr. wrote: Standard PC 1.44M drives will work fine as 720K drives as long as you ONLY use 720K DD media, most drives auto detect the media and adjust the data rate accordingly. The same is not true however for 1.2M 5.25" drives which IIRC must be told what rate to operate at, as the spindle speed is higher for 1.2M, and there is no density select hole as there is on 720K/1.44M. There are a couple of problems however, most 1.44M drives are jumpered to operate as drive 1 only, and cannot easily be changed, this can be fixed however by swapping lines in the cable e.g. swapping 10 and 12 will make the drive respond as drive 0. Also depending on your system, it may require a ready signal on Pin 34, most 1.44M drives supply disk change on this pin, however the couple of systems I have worked with that require this signal (Amstrad CPC, Spectrum +3), wiring the signal permenently to ground will do the trick. Note some of the older 1.44s may have jumpers to change the ID, and enable ready. I have some Teac FD-235F drives that are like this (they have a bunch of jimpers just to the left of the steper motor), unfortunatly the HF that you have does not. Unfortunatly I believe that the spindle speed in 1.44s is always 300rpm, even when operating in HD mode, and that is fixed in the drive, I don't think that's possible (with standard drives at least). Cheers. Phill. -- Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric ! "You can twist perceptions, but reality won't budge" -- Rush.