I'm doing a bit of a one-off project. A friend of mine has loaned me a Commodore VIC-20. The deal is, I can keep it for as long as it takes to fix it and then return to him. Bargain! (?)
During diagnosis I decided that I suspected the RAM chips. But it's only a hunch. There's 11 of them, all soldered in, so no way am I replacing them all on a hunch. So I need to do some proper diag. The machine doesn't run, so no options there. Only remaining option is to build a RAM tester.
And, after all that preamble, we get to what I'm building right now: a RAM tester for a vintage VIC-20 computer.