All of the PCBs have been assembled, now I'm assembling the computer and testing each system as I install each board.    I started off powering up the system board to make sure everything looked okay. I'll be connecting each module to this as the central hub. 

The first major system I tested was the RAM. I had to change two bias resistors to pull-down from pull-up because I made an error in one of my logic circuits, but otherwise it's good to go. 

Next I tested the flash memory. I'll need it to run any test programs, so I'll need it working reliably before I can test any more exciting systems (*coughs* CPU). I found a bug in one of the data protection circuits - an RC timer is connected to a buffer without hysteresis and causes ringing on the output. Fortunately, this system is somewhat unique in that the ringing is extremely unlikely to cause a problem, but if I make a new revision of the board, that will be one of the first things to change. 

Then I installed the control panel. There's not a whole lot to test until I've connected more boards, but already you can see some of the completed systems lighting up :)