FD-500 (26-3129)
Controler
This model is also mounted in a long cartridge. It appears to be identical to the 26-3029, with the exception that it carries the Tandy name rather than the TRS-80 name.
Driver
All subsequent drives were also white in color, but were mounted horizontally and used half-height drive mechanisms. They shipped with a single drive (Drive 0) in the lower 'bay', and a blanking plate over the upper opening. These drives could be upgraded to a dual-drive system by installing the second drive kit in the existing case. Note that the kit included, and all dual-drive installations in these cases require, a 12-volt cooling fan. The units run acceptably cool with a single drive, but not with two drives. The 4 cm diameter, 1 cm thick brushless fans (as used on many CPU heatsink assemblies) work well in these cases.