25 May
2003
25 May
'03
2:52 p.m.
On May 25, 17:32, Greg Elkin wrote:
The 11/34a I collected recently (BA11-L chasis, H777
PSU) and had
difficulty getting to power up is in better shape now that it's had a
good clean ; backplane inspected and all the dust & debris removed
from its slots (via "fart in a can", ie compressed air :), the cards
have had their edge connectors cleaned (india rubber) to be nice and
shiny.
Switching to DC ON, the fans whirr happily and the front panel now
has "DC ON" and "RUN" LEDs on, with 000000 on the 7seg LEDs.
If I try to halt (keypad CNTRL + HLT/SS), the RUN LED stays on and
BUS ERR LED also comes on.
FAQ. This is the result of having a 9302 terminator, whichg asserts
SACK, and a missing NPR jumper somewhere. Either you have a card
missing, or you've put a card that doesn't pass NPR into a slot where
previously there was a card that did (or you've put a small grant card
where you should have a full-size one). Ethan mentioned this in
response to one of your posts recently, and Tony (on more than one
occasion) explained in detail why this has the effect it does.
http://www.classiccmp.org/pipermail/cctalk/2003-May/022031.html
http://www.classiccmp.org/pipermail/cctalk/2003-May/022051.html
Don't feel *too* bad about it, I got caught myself with that, once.
--
Pete Peter Turnbull
Network Manager
University of York
25 May
25 May
4:11 p.m.
FAQ. This is the result of having a 9302 terminator,
whichg asserts
SACK, and a missing NPR jumper somewhere. Either you have a card
[...]
response to one of your posts recently, and Tony (on
more than one
occasion) explained in detail why this has the effect it does.
And I've just given a brief explanation _again_ :-)
Don't feel *too* bad about it, I got caught myself
with that, once.
Me too... And I once had a problem of a machine halting at the power-fail
trap vector (I think) which turned out to be due to a failed DIP switch
on a DL11 which made that device's interrupt vector the smae as the power
fail trap. As soon as RT11 booted and enabled interrupts, the machine halted.
It look a long time to find that one. Of course I spent most of that time
with the CPU boards on extenders, trying to sort out the power fail logic...
-tony
4:43 p.m.
Thanks Tony, Pete et al
I need to go over the backplane to find how DMA (NPR) grant thing is
wired on this sytem. Need to learn about Unibux, MUD and SPC and all
the other bits yet :)
With the M9302 terminator + SACK logic board removed, the front panel
now shows RUN briefly then BUS ERR when turning DC ON. And I can
deposit & examine data into RAM at 1000+. Trying to look at ROM at
777300 gives a BUS ERR again.
Whee, progress anyway from a week or so ago when I was worrying that
the PSU was not happy.
greg
7889
days inactive
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ard＠p850ug1.demon.co.uk -
ClassicComputers＠bouncy-castle.demon.co.uk -
pete＠dunnington.u-net.com