Tandy TRS-80 Model III by Radio Shack

    The article will focus on the Tandy RadioShack TRS-80 Model III - a 1980 retro computer based on the Z80.



    Many photos under the cut.



    The first computers of this series began to be sold through the RadioShack chain of stores in 1977. Model 3, which will be discussed in the review, went on sale in 1980.

    My instance number 26-1062 was sold with 16 kb of memory and a built-in Basic for $ 999.
    The marking is indicated on the bottom case.



    The motherboard and the case could not detect the release date, but judging by the marking of the chips, this is the end of 1981.



    The previous owner expanded the memory to 48 kb and installed a controller with two drives. A set of memory and drives at that time cost another $ 637.

    The computer also has an original dust cover. Computers were expensive at that time and they were taken care of :).



    The computer runs on an 8-bit Z80 processor with a clock frequency of 2.03 MHz, has a cassette interface, a 12
    -inch black and white display. Text resolution - 16 lines of 64 characters, graphic - 128x48. You
    cannot call it portable, the weight of the device is 16.5 kg.

    For this, there is also a computer graphic High-resolution graphics adapter with integrated 32KB of memory and a resolution of 640x240 pixels. it cost 369.95 this card



    in the computer, even advertising was Isaac Asimov





    about the popularity of the computer at the time said a large number of books on programming.



    Gender You can find the list here.www.trs-80.com/wordpress/books

    When you turn on the computer tries to boot from a floppy disk, it does not write anything on the screen, so at first it seemed that it was not working. To boot from the cassette or run the built-in Basic, you need to hold down the Brake button and press Reset.

    This prompt will appear and Basic will start:



    Fortunately, I got a floppy disk with TRSDOS v.1.3 and a small set of programs in the kit.





    Disk boot and Disk Manager operation are shown in the video review at the end of the article.

    From time to time, the controls for adjusting contrast and brightness stopped spinning on the computer, so I had to disassemble it to get to them. Next is a series of photos of the insides:

    Disassembled case:



    Motherboard:



    Power supply, it shows the release date - the end of the 81st year. BP itself was developed in 1980.



    Processor the Z80 :



    RAM. At the factory, 16 KB of 8 Mostek MK4315N were installed .
    When expanding to 48 Kb, 16 more TMS 4116-20JDL



    ROMs were delivered :



    Kinescope 12VCLP4



    Useful resources

    The most complete information about computers of this series
    www.trs-80.com/wordpress

    Available software
    ianmav.customer.netspace.net.au/hires/ hires.htm

    Demonstration of video games on TRS-80
    gdcvault.com/play/1015922/Inspiration-from-the-Trash-The

    Promotional video of the time
    www.radioshackcatalogs.com/videos/1981_trs80_model3

    Large archive of catalogs from Radio Shack
    www.radioshackcatalogs.com/computer.html

    My video review demonstrates the operation of a computer.

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