Model II Model III TRS-80 Model 4 TRS-80 Radio Shack
The Model I could not meet FCC regulations on radio interference due to its plastic case and exterior cables. Apple resolved the issue with an interior metallic foil but the solution would not work for Tandy with the Model I. The Model I also suffered from problems with its cabling between its CPU and Expansion Interface (spontaneous reboots) and keyboard bounce (keystrokes would randomly repeat), and the earliest versions of TRSDOS similarly had technical troubles. Though these issues were quickly or eventually resolved, the computer suffered in some quarters from a reputation for poor build quality. Nevertheless, all the early microcomputer manufacturers experienced similar difficulties. Since the Model II and Model III were already in production by 1981, Tandy decided to stop manufacturing the Model I. Radio Shack sold some 1.5 million Model I's. The line continued until late 1991 when the TRS-80 Model 4 was at last retired.
