MicroVAX 3300/3400

On Wednesday, May 26, 2021, 02:35:32 PM PDT, Zane Healy via cctalk <cctalk at classiccmp.org> wrote: [....] two points: 1. MS650-AA 8mb modules from a KA650 will work in a KA640. They won't work with a KA655 or a kA660 (or a KN210_. Those need the MS650-BA, or the 16MB MS650-BB, or the third-party 32MB modules. So if your KA640 is dead and you want to upgrade, you will likely need new memory, too. (You likely know this already.) 2. A few times over the last year, I've read an online service manual detailing how to turn a BA430 into a BA400X. That manual describes pulling the CPU and inserting the DSSI"paddle board" in the first slot. That manual should be. useful in understanding your nonstandard chassis. However, if I recall correctly, I think you need to remove the "paddle board" and put the CPU into the first slot, for bus-termination reasons. The memory modules need to move one slot over to match. I don't know if that will help with your diag failures, but it seems worth trying.