TRS-80 Model I
|TRS-80 Model I from 1978
||Z80 @ 1.77MHz
||Level II BASIC
||12" white CRT monitor (26-1201)
||video, cassette, power, expansion interface
||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.
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Last updated on
Tuesday, July 22, 2014