MicroVAX II

From: Tothwolf <tothwolf_at_concentric.net>
Date: Sun Nov 24 23:26:00 2002

On Sun, 24 Nov 2002, Antonio Carlini wrote:

> > I've since pulled all the boards, installed a M7625-AA (KA655) and
> > M7621 (MS650) 8MB memory card by themselves, and got a chevron prompt.
> > I also got a memory error and a message stating normal startup is not
> > possible. 'show memory' showed 0MB of ram installed. I tried another
> > 8MB board with the same results. I also tried 3 different 16MB boards,
> > but the LED display showed 'F', and of course, I didn't get a chevron
> > prompt.
>
> You know that the over-the-top connector used on the KA630 and the KA65x
> are different? I don't know exactly what failure you see if you use the
> KA630 OTP with the KA65x - but you may just have found out!

Which connector are you referring to? The KA630 and KA65x both use the
same console bulkhead, and in turn use the same two cables that connect
it. The KA630 and KA65x do of course use different memory boards, but the
ribbon cable that connects them is the same. Those are the only 3
connectors that I can think of offhand, except for the Q/CD bus
connectors...

> It seems odd that a PSU could cause this problem and I'd be surprised if
> *all* your memory boards are faulty (I've never found a dead one even
> after they'd spent quite a while floating round the lab).

Well, *none* of the memory boards are faulty :)

For some reason, they seem to not be getting clean power, so they are not
working properly. I won't know for sure until I get my scope probes, but I
expect to see lots of noise on the power supply output that happens to
power most of the chips on those boards.

-Toth
Received on Sun Nov 24 2002 - 23:26:00 GMT