TRS-80 Model I

 
 
TRS-80 Model I from 1978

CPU: Z80 @ 1.77MHz
RAM: 16KB
ROM: Level II BASIC
Display: 12" white CRT monitor (26-1201)
Ports: video, cassette, power, expansion interface
Catalog No.: 26-1006
Serial No.:
Catalog Price: $789
Notes: This unit has had several modifications installed: there are 4 switches (2 pushbutton and 2 toggle) added to the case. The upper left pushbutton is another Reset Button. The lower left pushbutton appears to be a Control key (Shift/Down-Arrow). The toggle switches are for a lower case modification. The system was not quite working when I got it: the video didn't sync. It turns out that there was a bad inverter in both the horizontal and vertical sync circuits. After I replaced two 74C04 chips (Z6 and Z57), it works fine.


Return to the Tandy Computers page.
Return to the Hardware page.
Return to the Old Technology Collection page.

Last updated on Tuesday, July 22, 2014