March 18, 2013 – Good news for Model I Owners

March 18, 2013 – Model I Power Supply Replacement Schematics


       
I receive a fair share of emails from people with Model I Power Supply issues. While common wisdom is to cut open those supplies and replace the fuse, sometimes that is not possible, that is not the problem, or the individual is missing a supply altogether. I had asked Ian Mavric to look into the matter and Ian has now advised that Dean Bear has designed a replacement power supply for the Model I. It has enough power to drive both the Model I and the Expansion Interface, so two will not be needed. The graphic to the left are designs for a 120V and a 240V, depending on your need. Of course, I have not tested these, and have no idea if they work (Dean has been running his for over a year and Ian and Dean will be testing these schematics shortly), so build/use at your own risk.
   
 

November 5, 2012 – Metatronics Extent-80

November 5, 2012 – Metatronics Extent-80


  

    Scot Silvestri provided some pictures of a Metratronics Extent-80 he found in the trash. The Extent-80 apparently allowed for up to 8 disk drives on a Model I.
    The product announcement in the 12/81 issue of 80 MICROCOMPUTING read …
            “Metatronics (a subsidiary of Meta Technologies Corp., as of September 1, 1981) introduces a unique device allowing the connection of as many as 8 disk drives to a TRS-80 Model I computer. Its integrated design is compatible with application software running under VTOS, LDOS, NEWDOS/80, NEWDOS+ and TRSDOS 2.3. Features include a U.L.-approved power supply, power-monitor LED, operating environment protection circuitry, high-impact metal case and gold-plated contacts. Complete with instructions and patch program diskette for configuring your favorite operating system.”         
    Glenn Emelko advised …
            I designed this product for MTC, and did all of the OS patches for TRSDOS, LDOS, and Newdos/80 personally. The device decoded the four drive address lines so that codes 1, 2, 4, and 8 (0001, 0010, 0100, and 1000) addressed the first four drives 0-3 directly. Other combinations of the drive select lines then selected subsequent drives allowing addressing of drives 4 to 7 (iirc it was 0011, 0101, 0110, and 0111 respectively), and we internally experimented with a 15 drive system using 8,9,A..E for the next drive numbers but never released it that way. One code 0000 was reserved for no drives selected. The operating system patches were tricky but once complete it worked great.         


(Click to Enlarge)

(Click to Enlarge)

October 16, 2012 – Another Author OK’s Download – NAME THAT SONG

October 16, 2012 – Another Author OK’s Download – NAME THAT SONG


  

    Arnold Gross has let me know that he and Rik Pierce hold the copyright to NAME THAT SONG (a musical quiz game) and that they are permitting it to be available for posting for everyone to enjoy. It can be downloaded in DMK Format here and the manual can be downloaded here.
    Since TRS-80 disks are very unlikely to hold data for the (approximately) 110 years of copyright; if anyone else is holding a copyright in TRS-80 software that they are willing to allow people to download, please contact me.


(Click to Enlarge)