Dual Floppy

December 12, 1993

My 1.2M FD that I had used with my 286BB, and now my 386BB, decided that it really did not want to work anymore, (Actually, it sort of still does, but give me a lot of errors/corrupted file messages that aren't real, as confirmed by other PC's). I seized upon the opportunity to buy a new Teac Dual Drive, one that has both a 5.25" and 3.5" in one 1/2 height case.

When I bought the thing, I noticed that there was only one (1) connector on back. The cable coming off the BB, has two (2) connectors, 1 before the twist, and 1 after. Well, I connected the last connector (after the twist) to the new drive. No matter what I did in BBsetup or PC Prefs, I could only access the 5.25"! When I connected the first connector, (before the twist) I could only access the 3.5"! In both cases, when the BB booted up, it would tell me about a drive failure, as if I didn't already know...;-). So now, I could access either floppy drive, but only one at a time with a cable change.
I concluded that the drives were working, but the BB or cable did not "speak" correctly. It turned out that it was the cable. Talking to Kelly, one of Harv Laser's friends, whom I had ordered a couple of external 3.5" SCSI cases earlier in the day, found out which pins on the BB cable were what.

The twist of the BB cable consists of pins 10-16.
They are labelled as follows before the twist;

Pin 10 - Drive Select 0 (DS0)

Pin 11 - GND

Pin 12 - DS1

Pin 13 - GND

Pin 14 - DS2

Pin 15 - GND

Pin 16 - Motor On

Kelly concluded that since software drives whether accessing drive A or B, that the drive motor was not enabled. I jumpered pin 16 and 12, before the twist, and voila, both drives work! If you connect the connector on the BB cable after the twist, the 5.25" will be drive A and the 3.5" will be drive B. I did not like that, so I connected the connector before the twist, and now I have the 3.5" as drive A, and the 5.25" as drive B. Making the jumper permanent was no problem as the drive comes with a 34 pin to edge connecter converter, and I just soldered the jumper there. Of course, I have told BBsetup which drive is which size. PC Prefs also knows that both drives are internal.

I had not seen any information on the nets that addressed the "Dual Floppy Drives", both Teac and now I think NEC makes them too, so that's the reason I posted these tidbits.


Since posting this article on UseNet (comp.sys.amiga.emulations) several people have e-mailed me, about having no problems with their Teac or Cannon dual-drive out-of-the-box with their bridgeboard. Maybe I got a lemon..., but the drive has been working great for over 2 months.

Text based on BBFAQ © Sébastien Boisvert
Last Update: 20.07.2023