[Coco] FD501

Darren A. darccml at hotmail.com
Tue Nov 21 15:10:14 EST 2006

>I picked up a TANDY FD501 complete. First original TANDY FD I've ever
>owned. Drive 0 only. Only one R/W head, unfortunately. What I find
>curious is that both the DS0 and the DS1 bridges are soldered (not to
>each other), as if the appropriate jumpers were in place. I checked the
>ribbon cable and it appears fully intact and original. I've not had the
>chance to try it out. Is it normal for these units to have DS0 *and* DS1
>jumpered? Can't figure that one out.

Yes, my FD501 also has both DS0 and DS1 connected. Tandy's method of drive 
selection was to remove the appropriate contacts from the edge connectors on 
the cable.

>Other thing. The RS Disk Basic ROM is the old smaller variety. Is it
>possible to rig a 27xxx chip into there?

Cloud9 sells (used to sell) an item called the DOS Adapter. It was a nice 
little board that allowed a 28-pin (27xxx) EPROM to be plugged into the 
24-pin sockets used by Tandy. Whether or not you can still get one is 
another matter. There are instructions floating around the web that show how 
to make your own adapter with multiple piggybacked sockets, but it's a real 
hassle, and it makes the cart too big to fit in the coco.

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