Troubleshooting a Broken Homemade Computer – Pet Hair is One Possible Culprit
BlondiHacks’ homemade Veronica computer, originally constructed in late 2011, recently went down for the ‘first time ever.’ In this fun post BlondiHacks walks through the troubleshooting process and suspicions that arise along the way – I too have had an encounter with errant pet hair disrupting card slot connections! (How did that hair get there to begin with?!?)
I started to probe the address lines of the RAM. This would give me a sense of whether the CPU was trying to access it. One of the reasons Veronica does a RAM check at startup is because that causes the address lines to be accessed in an ordinal fashion. That’s very handy for debugging all manner of bus and memory related issues. Having the machine exercise itself in an orderly fashion at startup gives you patterns to look for. It’s not really so much about testing the RAM itself. Modern SRAM chips pretty much don’t fail, and the visual effect of scanning through the RAM at boot is as much about nostalgic fun as anything.