MicroVAX 3300/3400

[Zane Healy]

On May 26, 2021, at 3:38 PM, Jonathan Stone <kiwi_jonathan at yahoo.com> wrote:
> 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.)

THANK YOU!  I didn’t realize this.  I’m not sure what the modules are in the MicroVAX 3, or how big they are.  They’re in a computer rack that requires some effort to access, so I haven’t gotten to them yet.  It sounds like I’d best have a look at RAM...

> 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.

Do you happen to know what Manual this is?  I’ve spent a lot of the last couple days reading up on the BA430/B400X, and the KA640/KA660.

Zane