I've finally acquired enough of the missing boards to try for a console
prompt. But I want to do this carefully. I don't want to fry any of these
modules if my power supplies are not on spec.
I'm still waiting for a power key that's in transit (graciously copied by
another classiccmp'er), but I figured I could just set the power controller to
local and crank it up.
So, after cleaning and reforming the removable capacitors[1], I figured
that I wanted to apply power to the system with all the loads removed, and
confirm proper voltages on the outputs.
I left the backplane completely empty of boards, and I disconnected the
power cable to the TU58 controller, just to be safe. I get a good AC
indication on the controller when I plug into the main AC supply circuit.
Switching the breaker on and the control switch from OFF to LOCAL gives
good air from the (loud!) blower, but...
What I see on the power controller indicators is the '+2.5 FAIL' and 'REG
FAIL' LEDs both light up, then several seconds elapse and the 'OVER
VOLTAGE' LED will flick on and the REG FAIL flicks off for about 1/2
second, then the whole sequence repeats. Each cycle takes about 8
seconds. A couple of photos of this can be found at:
http://www.rogerwilco.org/VAX11-750/psfault
I admit that I've never dealt with such a complex power system before,
and I've just spent the last hour or so reading through the 'VAX 11/750
H7104 Power System Technical Description' document that I found on
vt100.net. Trying to get my brain around what's going on, I came across
the fault isolation section and it seems that what I'm seeing on the Power
Controller LEDs maybe indicates a "Fault in the CPU backplane".
Of course, there is no CPU installed yet. Could this indication be normal
when no boards are installed?
I'm hesitant to install any of my precious boards until I'm convinced that
the power supplies are good, but maybe I have to install one (or more)
boards to actually close the loop on something.
Further reading tells me that there is a +2.5V-at-the-backplane monitoring
function in the +2.5V power supply. I haven't yet looked at this particular
issue up close, but maybe the monitor circuit is not complete without the
proper board in the backplane. Is this a sensible explanation? I just want
to be sure that putting one or more boards into the backplane is a safe
next step.
Thanks!
- Jared
[1] System hasn't been powered since 1994. I went through the motions,
but I don't think the caps needed any help; the readings during the
reforming process seemed to show them in good shape from the start.
Hi,
I've got a pair of AlphaServer 1000A systems available for free to whoever
wants them. I need the space.
These were previously rack-mounted, include memory and disk, and
were working last time I powered them on.
I'm near Plymouth Meeting, PA, USA, about five minutes from the PA
turnpike exit.
Please email me if interested.
Mark
--
Mark G. Thomas (Mark at Misty.com)
http://mail-cleaner.com/
Regular drill bits will work fine as long as you go slow and easy -
especially when you are about to "break" through the other side. Dull
bits work better. The bit the salesman was trying to get you to buy was
actually a bit designed to scrape the plastic instead of cutting it.
The angles are different on the bits.
Also, when using screws to join your pieces together be sure to drill
your holes slightly larger than your screws. This allows for some
movement of the plastic and prevents breakage at the stress point.
--- Michael Lee <mikelee at tdh.com> wrote:
> I just received an old-ish (1990) Toshiba T1000LE
> laptop and it wouldn't
> boot, so I took a look at the hard drive and there
> seems to be some type
> of goo oozing out of it. It's a Conner hard drive,
> nothing too abnormal.
>
> I didn't think a hard drive contained anything that
> could ooze out. Any
> idea what it could be and does that mean the drive
> is pretty much
> toast? Let the magic goo out?
-------------
I've had that problem with a Conner drive in an Ogivar laptop; it was
the gasket between the housing and cover decomposing the same
way as drive rollers etc. My drive was still working though and, after
removing the goo and wrapping a layer of tape around the perimeter,
still is (at least so far).
m
> is it likely that I'll
> be able to read it on the programmer like a standard PROM/EEPROM?
Most likely. You will need to verify on the schematic that they didn't
use the extra lines to control programming as chip selects, though.
From: Richard <legalize at xmission.com>
In article <474E0308.2010901 at atarimuseum.com>,
"Curt @ Atari Museum" <curt at atarimuseum.com> writes:
> There was an urban myth back in the late 80's and early 90's that there
> was a virus going around that could alter the scan rate of a video
> adapter so that it would blow out the monitor. Never saw any such
> damage to a monitor in person, so I don't know if it was just a myth or
> actually existed.
Its not an urban legend. The issue was that there was a sync register
(horizontal sync, I think) for which you could poke in a zero value.
Wasn't the issue with a MONO monitor rather than CGA? ISTR that the horizontal
frequency would get altered overheating the flyback with the resultant loss of
the magic smoke.
