Upon the date 11:44 AM 4/21/99 -0400, CLASSICCMP_at_trailing-edge.COM said
something like:
>>> Speaking from decades of experience, you *do not* put a Unibus machine
>>> together in a big configuration, especially from mix-and-match used
>>> parts, and get it to work. You go down to the most basic configuration
>>> possible, and then add parts one at a time, testing as you go.
>
>>Well, with the exception of the DELUA, and RAM everything is configured the
>>way it was when I got the machine, but that's a good point.
>
>I hope nobody takes it as an insult when I try to encourage them to take
>a system down to its bare-bones and build it back up step-by-step, but
>this really is the best way to debug a system that one knows little
>about the history of. Just because something is written on the sticker
Amen brother! That is the best way to approach problem solving: Get the
parts which can be, or at least contribute to, the problem out of the way
-provided those parts are options and/or not integral to the basic
startup/running of the machine. Sort of like cutting the brush down to see
into the forest.
That's where I'm at with my 11/34A, a slow-moving project. Seems when I put
the project aside a couple of weeks before Megan started work on hers, the
bus was hanging for some reason. I've got to find and check the bus grant
lines through to the terminator first. Tricky for me as this is the very
*first* Unibus, or even DEC for that matter, hardware I've had the pleasure
to work with. The backplane connector pinouts are wierdly strange to me so
far :) I'm used to the numbering scheme found on VMEbus, STDbus and even
that infernal ISA bus as opposed to the DEC folks here who may see it in
their sleep;) But I'll get the hang of it eventually. It'll just take me
that amount longer to get the machine running.
I need to remove the FP11 and cache modules and try to see if it can do
stuff w/o hanging. I'll get back to you DEC folks in another week or two
about this if I have a pothole of trouble to leap over:)
I must get back on it as soon as I get the final clean-out and fix-up of
our old house completed so it can be sold. That's been putting much
pressure upon me recently. It takes up time I want to use for getting the
/34A running to sort out some RL01/02 disk packs before the balance of them
head out west with the rest of the gear heading out. I only take timeout to
*try* to keep up with this and several other mail lists (about average 120
to 170 msgs total per 24 hrs. Sometimes over 200 with loo-ong threads like
several of the decidedly *off topic* threads which have come thru this list
in the past weeks :(
>on the cover of a system about its configuration doesn't mean that it
>was working in that last configuration! In particular, with Unibus
This is true. I was told that it *may* have worked when I picked it up. But
the previous owner likely may not have remembered correctly (it was over
five years since he turned it on) as I couldn't get it lit up last Autumn
by using the original RK07's.
>machines you have to check the presence of the NPG jumpers on the backplane
>if you have the slightest reason to believe that the configuration has
>been meddled with in the slightest since it last worked. A single
>mis-placed jumper anywhere in the system can cause the entire system
>to lock up when the first DMA attempt is made...
Briefly, which are the NPG jumper pin numbers again?
Any other jumpers or ww connections I should check out? I'm not blessed
with a complete set of printsets and/or tech manuals so some important tips
may not be found by me. I've been trapped by problems caused by lack of
correct or detailed info on this already.
Thanks much. Regards, Chris
-- --
Christian Fandt, Electronic/Electrical Historian
Jamestown, NY USA cfandt_at_netsync.net
Member of Antique Wireless Association
URL:
http://www.ggw.org/awa
Received on Wed Apr 21 1999 - 12:28:59 BST