TRS-80 Model 16B - 8 MB RAM Upgrade - Part II: DMA Burst Mods

Part two in my quest for 8 MB of RAM on my Radio Shack TRS-80 Model 16B! In this video, I perform four modifications in Tandy Technical Bulletin TB 12/16B:44 on the 6 MHz “short board” 68000 CPU card. These upgrades enable the DMA burst mode functionality required to use XENIX 3.x un-patched, as well as correcting PAL and other issues that were revised on 8 MHz versions of the 68000 board. Music (in order) None – just me prattling on endlessly. Chapters: Project Intro / Attempting Boot of XENIX 3 (0:00) The Mod Kit (1:46) A Look At The 68000 Card And Mod Process (3:02) U48 PAL Upgrade and U36 Prep (5:45) Knife-to-Board: BERR and WAIT Modifications (8:12) First Test Boot…And Failure! (13:43) Second Attempt…It Works! (15:08) What’s Next / Outro (16:22) I do these videos unscripted, so I apologize if the in-the-moment descriptions of things are a bit scattered. If you have any questions/comments about this video, you can find me in any of these f