Image Map Image Map
Page 5 of 5 FirstFirst 12345
Results 41 to 42 of 42

Thread: Adding lowercase to a Model 1 in 2016

  1. Default

    Ah, the lower case mod. I almost forgot about that. I don't remember which one I did but I thought it was the coolest looking mod. The lack of descenders made it even more interesting to me somehow. Once installed I immediately started loading old BASIC code and swapping the uppercase text for lowercase text and saving it again to Cassette. Fun!

  2. #42
    Join Date
    Dec 2017
    Location
    Edinburgh, Scotland, UK
    Posts
    6

    Default

    I shared pjhacnau confusion about just exactly what was required to modify a Rev G mainboard to have lower-case. Having figured it out I thought I'd share it so that the information was all in one place/post.

    To carry out the mod:
    - Obtain at least one new MM2102 1K static ram chip. I found these available easily on ebay and aliexpress though there's a bit of a wait and out of 10 chips I ordered only 7 were good...
    - Get a screen memory test program. I used "diag" from https://www.classic-computers.org.nz...mem%2Bdiag.htm
    - Check each RAM chip to be used by swapping them in to Z46 in turn
    - Bend out pin 11 and pin 12 on the chip that is to be the top in a piggy-back
    - Assemble the two chips taking care to only attach them at the very top of the legs of the bottom chip. This is necessary to avoid fouling the Z46 socket
    - Cut the thin trace that is located between Z29 and Z30 (see picture below). This connects Z30p13 with Z27p13 (and thus onwards to Z60p4)
    - Run a patch wire from Z46(top)p11 to Z60p5
    - Run a patch wire from Z46(top)p12 to Z60p4
    - Run "diag" to test the new screen memory. It also has a character generator test which can be used to verify that all is well with the mod

    model1-lower-case-track-mod.jpg

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •