Well I did desolder the Bourns filter behind the floppy connector, but it hasn't solved the problem. In fact it seems to have added another problem, because the disk no longer spins up. On power-up, the drive does its self-alignment by seeking Track 0. The floppy request icon comes up, but with any floppy inserted the icon alternates between floppy request (the question mark) and floppy bad (the X on the floppy icon). Also the servo eject does not occur, though I hear that servo motor clicking as if it is receiving single-step instructions but not moving anything. It will sometimes run the eject sequence after I press the eject button on the 800k drive itself. So it seems commands are not reaching the drive, including the motor on command. I'll look for a source for replacement filters or make them if necessary, but their might be some other problem as well.

I'm going to have to trace this out more thoroughly to see where the signals go between the floppy port and the IWM chip. I hope schematics are in the mail. Can't find anything in the Pina books that gets down to this level on drive issues.

Rick