5 Jun
2003
5 Jun
'03
12:43 p.m.
On Jun 5, 16:19, Tothwolf wrote:
Since we are on the subject of VAXen...
What would be the most likely problem with a BA123 MicroVAX II that
powers
up, but sometimes totally locks up during the
diagnostics? (I'm not
even
sure it can boot, as some of the RD53s sound a little
sick.) I've
pretty
much eliminated the boards as the cause, and the only
things left are
the
backplane and power supply. It does have those older
power supply to
backplane wiring harness cables, which I guess I need to replace
before I
put many boards in the card cage.
Could be voltage drop between PSU and backplane, resulting in low
voltage on the cards. Part of the problem with the harness (which was
discussed here some months ago, in a different context) is that parts
go high-resistance. Check the voltage (especially the +5V) on one of
the cards.
--
Pete Peter Turnbull
Network Manager
University of York
6 Jun
6 Jun
10:30 a.m.
On Thu, 5 Jun 2003, Peter Turnbull wrote:
On Jun 5, 16:19, Tothwolf wrote:
I checked the voltages on the drive harnesses, and +5VDC and +12VDC seemed
to be within the normal variance. I'll see if I can't check +5VDC on some
of the boards too. I guess if that checks out ok, I'm to where I started,
thinking that there may be noise on +5VDC and/or +12VDC. Has anyone else
had similar problems with the BA123 power supply?
-Toth
Since we are on the subject of VAXen...
What would be the most likely problem with a BA123 MicroVAX II that
powers up, but sometimes totally locks up during the diagnostics? (I'm
not even sure it can boot, as some of the RD53s sound a little sick.)
I've pretty much eliminated the boards as the cause, and the only
things left are the backplane and power supply. It does have those
older power supply to backplane wiring harness cables, which I guess I
need to replace before I put many boards in the card cage.
Could be voltage drop between PSU and backplane, resulting in low
voltage on the cards. Part of the problem with the harness (which was
discussed here some months ago, in a different context) is that parts go
high-resistance. Check the voltage (especially the +5V) on one of the
cards. 
1:06 p.m.
I checked the voltages on the drive harnesses, and
+5VDC and
+12VDC seemed to be within the normal variance. I'll see if I
can't check +5VDC on some of the boards too. I guess if that
checks out ok, I'm to where I started, thinking that there
may be noise on +5VDC and/or +12VDC. Has anyone else had
similar problems with the BA123 power supply?
What does the console output look like when it locks up?
--
---------------
Antonio Carlini arcarlini(a)iee.org
6:26 p.m.
On Fri, 6 Jun 2003, Antonio Carlini wrote:
It locks up during the diagnostics, most often during the memory tests.
I've managed to get it to go though to the point where it was ready to
boot a couple of times. It seems to get worse if I leave the system
powered up. I know its not the boards, since I've tried known good sets.
-Toth
I checked the
voltages on the drive harnesses, and +5VDC and +12VDC
seemed to be within the normal variance. I'll see if I can't check
+5VDC on some of the boards too. I guess if that checks out ok, I'm to
where I started, thinking that there may be noise on +5VDC and/or
+12VDC. Has anyone else had similar problems with the BA123 power
supply?
What does the console output look like when it locks up? 
7 Jun
7 Jun
1:24 p.m.
It locks up during the diagnostics, most often during
the memory tests.
I've managed to get it to go though to the point where it was ready to
boot a couple of times. It seems to get worse if I leave the system
powered up. I know its not the boards, since I've tried known good sets.
As others have suggested, check the power lines _at the backplane or
boards_. This really does sound like a power problem, but it might be
something like a bad connection in the power harness which causes the
voltage at the backplane to be too low, while the PSU output (and the
voltage at the drives) is fine.
Also, if you have a 'scope (and if not, why not?), check for ripple on
the power lines.
Have you checked the power fail lines (ACLO and DCLO)? Strange things
happen when they get asserted at random...
-tony
7716
days inactive
7718
days old
4 comments
4 participants
participants (4)
-
arcarlini＠iee.org -
ard＠p850ug1.demon.co.uk -
pete＠dunnington.u-net.com -
tothwolf＠concentric.net