[Coco] Tandy Controllers

[Bruce W. Calkins]

----- Original Message ----- 

From: "Steve Ostrom"

> How many different disk drive controllers did Radio Shack/Tandy release? 
> I think there are at least 5.  Two long ones numbered 26-3022 and 26-3029, 
> as well as three short ones numbered 26-3129 (FD500), 26-3131 (FD501) and 
> 26-3133 (FD502).  Were there significant differences between each of 
> these? Were they renumbered because of ROM differences?  I think the long 
> vs. short had different power requirements (12v vs. 5 v?).
>
> -- Steve --



The 26-3022 needed 12 volts and had an adjustable part that could be "fun" 
to set correctly.  All of the other Tandy/RS controllers were 5 volt only 
and used an upgraded chipset.  The ROM difference had nothing to do with the 
controller number, although by the time of the 26-3029 most of them had the 
1.1 ROM.



There were several third party controllers too, at least one of which does 
not work with the CoCo 3 under OS-9 Level 2 due to timing issues related to 
it's different chipset.



Bruce W.