DEC KA650 VAX memory troubleshooting (video)

sorry, the technical manual actually, which has an architecture *chapter* http://www.bitsavers.org/pdf/dec/vax/650/ The idea, eventually, is that I will publish my notes so that you wouldn't need the logic analyzer, at least for the 8MB board. I just had it hooked up, so I demoed it. The notes will include a mapping of bits and adresses to ICs so that you can narrow down which chip from just the ROM monitor. I don't have a 16MB board, but somebody could honestly probably figure out the mapping with a logic probe if they had to, just probe /cas while writing various test addresses, then check the data line while writing various test patterns. I also came up with some data that produces useful ECC bits, like all 1s, all 0s, one bit set only, and one bit clear only. That will also be in the notes when I write it up. On Sun, Jun 16, 2019, 3:25 AM Rob Jarratt <robert.jarratt at ntlworld.com> wrote: