The Tandy TRS-80 Model 4D computer

File under: You can find the darnest things at the transmitter site. Near as I can tell, this computer dates from about 1985 or so, it looks remarkably like my Apple IIe of the same vintage.  We used an earlier model TRS-80 in high school, that model had a cassette deck as the data storage device.  These have 5 1/4 inch floppy disks.  I used my Apple IIe as a gloried type writer, mostly for college papers.  I did manage to write some basic programs, no doubt copied from somewhere else.

For the day though, saving something for later editing, even to a floppy drive, was an order of magnitude over the single spaced type written page.

Tandy TRS-80 Model 4D computer
Tandy TRS-80 Model 4D computer

There are actually two of these computers, serial numbers 7086 and 7128.  I have no idea whether they work.   I’d donate them to a museum if there were one that was interested.  Otherwise, they may sit in the corner for another twenty years or so.

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9 thoughts on “The Tandy TRS-80 Model 4D computer”

  1. I remember the beast. It was a far cry over IBM punch cards, the IBM 1620, and Fortran which my computer class was all about in college. I decided to wait a little while and bought the Heath H-89 which was a cut above the TRS-80. And as the technology train roared by, my hard-sectored floppy drives became obsolete about a year later with the IBM PC. I bought one of those too. It would seem that the personal computer progressed almost exactly like the early days of radio, although faster and more complex. The progression of the crystal detector, regenerative detector, TRF, super-regenerative detector, and superheterodyne receivers is similarly followed 70 years later. The processor in my IBM PC ran at 4.77 MHz., and my current H-P runs at 3.2 GHz.. The only difference I see is that the American manufacturer (and worker) is almost completely left out of the equation.

  2. If you still have one or both of these TRS-80 Model 4 computers,I’d be interested in having them (or one) donated to our academy. We’ve have a small computer lab with some more modern systems, but we’re going to be teaching several youth courses (starting this mid-summer) about:

    “The History of Micro-computing”


    “Birth and Advancement of the Information Technology Age”

    If you’ve already donated these systems, we’d would appreciate any “leads” you may have on any other TRS-80 Model 1, III, 4D, or 4P. We’re also looking for Kaypro II, IV, X, 4/88

    Thank you much!

    Rei Horace, Director of Academics
    Sacred Fruit Institute
    Southern California

  3. Ah yes, got Paul, and Thanks for the response.

    I now know/remember which inquiry your email was about.

    Where are located (where will these be shipping from)?
    What condition and/or working state are they in?
    Are there any accessories, software disks, os disks, manuals, etc.?

    Thanks again Paul!


  4. And ah . . . looks like this site may have the information resources to assist interested “newbies” in setting up and operating a basic hobbyist ham radio station. Is this correct?

    If so, what/where would be the best place to start?

    Some of our students have expressed an interest in ham radio and wanted to know what it would take to get a decent “lab” station up and running.

    Thanks again,

  5. as a pure curiosity, are there any model 4D left? I am a restorer and thru the years I have gathered “pieces” of model 4 and 4D and trying to find an example model to ensure my restorations are precise and not “hack jobs” even pictures of the internals (specific drives used etc.) would be most helpful. much appreciated

  6. Patrick, the Model 4D has been reclaimed by the previous user. It was completely original, as I recall.

  7. This is amazing! Is there another Tandy TRS-80 available? I work at Tàndy, which is no longer associated with computing however, they do have a small museum and one of these belong on display. If there is one available I’d like to discuss acquiring it. Thank you!

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