30 Nov
2012
30 Nov
'12
8:44 a.m.
After a bit of time away, I had time to allocate to finally attempt to resolve this issue,
and apparently the problem was with one of the 16MB RAM cards. I have some other
RAM cards, but the ribbon connector was in a slightly different place, so I am not sure
its for the same era of machines (its a bit higher up on the PC Board... but it is QBUS.
Right now its working as a grant card.
Thanks, everyone, for the help with this.
Kevin
Date: Thu, 1 Nov 2012 16:31:37 -0400
From: mcguire at neurotica.com
To:
Subject: Re: Microvax II won't boot, hardware error?
On 11/01/2012 10:23 AM, Kevin Reynolds wrote:
Are these cables standard 50 pin ribbon cables
like those which would be used
to connect up scsi drives internally? Does length matter? I suspect that maybe
the cable is bad, but I don't have a replacement (the one in place is a 3 position
cable that is quite short), and no tools to crimp a new cable of this type. I do
have a few 5 position cables, but before I start trying random things, I am
hoping to understand the cable more specifically. The cable appears to be
straight through, but the connectors might "twist" connections. There could
be some ground plane factor, right?
They area ordinary ribbon cables with ordinary connectors.
Straight-through, no "twists". They don't have to be kept super-short,
but do keep them as short as possible. This is a memory bus, after all.
I don't know if there's a max length spec (DEC probably didn't envision
people putting random cables in there) but I'd try to keep the whole
thing to less than 6" or so.
-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA