Populated PCB with fix for unneeded inverter


Lots of progress but little time to talk about it.

Here’s the fully populated card installed.  There were two issues identified so far with the PCB design.  One, the battery holder silkscreen was upside down.  The second fix involved an inverter that needed removed whenever we decided to migrates from a flip-flop(74LS74) design to a SR NAND latch made out of NAND(74LS00) gates.

The memory tests are passing at 100% now!@#

However, there is still a minor issue with how the card responds on bootup, and I’m investigating!



Amateur Electronics Design Engineer and Hacker


  • Thanks Ralf!

    It’s really coming along. I’ve spent about two months of nights and weekends on this, and I’m happy with the speed of the project.

    Once I get this locked down tight, there’s a few other things I want to tackle, too.