Populating the ALU board

I decided today was a good day to populate the Arithmetic Logic Unit board I had fabricated in March.

I taped the bare board to my solder station workbench (which is separate from the one with all my test gear), then taped the solder stencil down as well. I scooped some solder paste onto the back of an old credit card and used that as a squeegee to apply the paste. The first time I got about half way done before I realized the stencil had slipped and the holes weren't lined up with the footprints, so I removed the stencil and wiped the board clean. Solder paste is sticky and hard to remove, but some 91% isopropyl alcohol on a rag made a quick job of it.

Testing the Instruction Pointer board

My project for April and May was to extend my PicoBlaze-based test framework to test the Instruction Pointer board I built in 2012. I also wanted to update the desktop computer in my electronics lab.

I'd completed the Verilog implementation of the i4004 CPU at about the same time I assembled the IP board, so the obvious way to test it was to strip out the parts of the Verilog that implemented the instruction pointer, and let the IP board perform that function. It seemed to work, but later, when I attempted to run the i4004 Clock program on the hybrid setup, it wasn't stable. Sometimes it would run, and sometimes it wouldn't. I wasn't sure why, but I didn't have a way to capture the failure for analysis.

The most costly phrase

You know what the most costly phrase you can say is? "While you're in there..."

Not my computer

I've said it while I was discussing work to be done on my car. Suddenly a job that should have cost a couple hundred dollars now costs a couple thousand. I went in to get the oil changed and the tires rotated and I said, "while you're in there... the air conditioning seems weak." It turns out that replacing the A/C compressor on my car costs a bit over $2k. But it's about to be summer, and it gets hot and humid here.

The same applies with computers. My primary desktop computer crashed a few days ago. The first attempt to reboot hung. The second got as far as the boot menu before powering itself down. The third reboot wouldn't even bring up the BIOS.