Floppy Cables & "twists"

After recently selling my ImageDisk system, and having a few spare older PC mainboards - I decided to make another - I did find a board that seems to have a decent FDC - it does all single density formats (many don't). Alas, it is "slightly newer enough" to only implement one floppy drive on it's interface - floppy B: does not appear at all to the system. Ripping the cable off the front panel drive to connect an external one is somewhat painful - Since the PC normally has a twisted cable to swap Select1&Motor1 with Select2&Motor2 to put each set on Select2&Motor2 of different connectors, I thought I could just use a flat cable and add a switch near the PC end to switch Select1&Motor1 to go to either Select1&Motor1 -OR- Select2/Motor2 on both connectors with the internal drive set to 1: and a cable coming out the back for drives jumpered as 2: That way I could just "flip a switch" to choose between internal drive 1: or the external drive(s) 2: (either would appear as A: depending on the switch). But when I try to access a drive jumpered as 1:, it does select, but the motor doesn't turn on. This happens even without my "special" cable. If I connect the drive (by itself) on the PC side of the twist on a standard cable, the motor doesn't work. The twist swaps Select1&Motor1 to Select2&Motor2 on the farthest connector, and since a standard drive is jumpered as 2: - This should put the 1: signals to 2: for a drive in that position - all other wires are "straight through". It looks as if some other signals is expected to behave differently when the drive is jumpered as 1: (I've tried this with a couple of different drives) - anyone know whats going on? Dave (I can use the message archive to check for responses every few days, so replying here is OK). -- ---------------------------------------------------------------------------------- Search "Dave's Old Computers" see "my personal" at bottom!