EEVblog #645 – TRS-80 Model I Retro Computer Teardown


Dave looks inside the most popular microcomputer of the 1970’s, the Radio Shack / Tandy TRS-80 Model I
And also a look at the TRS-80 Model 102.
Bonus EMI testing for fun.
Bonus rant on how slow the Tektronix MDO3000 is in RF mode.

TMS4116 16Kb DRAM
Level II BASIC Reference Manual
Forum HERE

Hi-Res Teardown Photos:

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    • Han Solo

      Haha. I had been seeing that on the shelf behind the new teardown bench, and I at first thought it was a TRS-80, but started to wonder if my eyes were playing tricks on me.

      My first computer was a TRS-80 Model 1. Learned quite a bit of Basic on that thing, and played some Lunar Lander. It was a good first computer before I got a C-64 the first day they were available in our town.

    • John Senchak

      I used a Trash 80 model 3 in high school around 1993 running DOS programs

    • Mike Willegal

      Love the 70’s era hobby computers. The TRS-80 of that era usually came with a cassette tape recorder for mass storage. Criteria is debatable, but in my opinion, the first practical hobby computer was the SCELBI 8H, advertised in the HAM magazine ‘QST’ in march of 1974. The is before the MITS Altair and the more well known Mark-8. It used the Intel 8008 processor, supported up to 4K of RAM and had 6 input and 8 output ports. It was a very well regarded system in it’s day. Once the 8080 based Altair came out, SCELBI couldn’t compete on price or performance and the company turned to publishing hobby computer literature.

    • John Cochran

      The clock speed difference that was mentioned actually indicates that the TRS-80 was slower than the apple. A rough comparison was a 6502 at a given clock frequency was approximately equivalent to a Z80 at twice the frequency. Although the Z80 was a lot easier to program with a much richer instruction set.

      • silverdr

        Depends how you define “easier”, of course.

    • Good old Trash 80. I remember spending tons of time at Radio Shack playing with these things. I wanted one but had to settle for the Timex Sinclair 1000 that was purchased at the local Canadian Tire.

    • blipton

      Didn’t see the link for the TRS-80 teardown, so just in case anyones interested:
      https://www.youtube.com/watch?v=Prl6D7bqQo8

      Also how did you know that the wall wart is a linear regulator and not a big transformer?

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