Hi,

Last night ...

I cleaned up my power hookup. Still hardwired to my circuit breaker
box in the garage, but now I have all wires connected, including 
neutral and pGND. I somehow found it useful to connect one black
wire in P1 and the other black and the brown wires together into
P2. Then 0 to 0 and pGND to pGND (which happens to be 0 as well
in my main switchbox.)

After that was done and the breaker and T-switch engaged, I measured 
output at the receptacles and that was fine. 110V properly with neutral
and ground where they should be. Very nice, but irrelevant for the
VAX itself.

Turned the key and "wroooom ..." it ran for about 10 seconds
and then it stopped again. On the mains 300 V box I saw two 
LEDs light. A green "BIAS OK" a red "FAULT" was on. And there's
another green LED "300 V" that was off.

I'm afraid I have a low-voltage situation here. It may be because
I trashed one or more of my thyristors last time (haven't 
repaired or replaced anything yet.) However, let's think again
if may be it cannot even work. From memory I recall the plan
be as follows:

        +-------+-------+----------
        |       |       |        .
       ---     ---     ---       |
        A\      A\      A\       |
        |       |       |        |
L1------|-------|-------+        |
L2------|-------+       |      = 300 V
L3------+       |       |        |
        |       |       |        |
       ---     ---     ---       |
        A       A       A        |
        |       |       |        .
        +-------+-------+----------


Question is, where does neutral connect to? Earlier, Carl
Lowenstein recommended to connect P1 to L1 and, say, P2
to L3 and leave L2 open. I have no idea though where 
the neutral line connects to? Bob Schaefer reports that the
neutral has nothing to do with the power & logic box. In
that case I should have things wired right, i.e.,

P1 - L1
P2 - L2 + L3

Carl, why do you think I should leave L2 or L3 open? Is this
better for symmetry reasons?

Since Bob has found that neutral is not being lead into the
power & logic box at all,  this would mean that the fact
that I did not connect neutral the first time could not
have hurt my vax. But she was hurt, so, I can still not
count on things being right.

I don't think that I really have more than 220 V power,
even though my AC voltmeter may say 5 V more. It's always 
a little off. In Germany I measured 230 V quite often. Here 
I am closer to 220 V. But 220 V * 1.414 is about 340 V which 
is 40 V too much. So, it's possible that something is blown
up, OTOH, our power & logic box should not feel anything
different from Geoff's and Geoff's does work. And how
did Geoff connect things? He did it like this, didn't he:


        +-------+-------+-------------
        |       |       |        .
       ---     ---     ---       |
        A\      A\      A\       |
        |       |       |        |
P ------|-------|-------+        |
    ----|-------+       |      = 300 V
    ----+       |       |        |
        |       |       |        |
       ---     ---     ---       |
        A       A       A        |
        |       |       |        .
N ------+-------+-------+-------------


Geoff, is that right that you connected your N before the 
diodes? Why did you do that? Why did you not just put N
on L2 or L3? And how did you do this? Where did you 
do this rewiring?

If your's is working then may be I should connect like you
did, and use P1 where you have P and P2 where you have
N?

However, from the way the machine acted today (i.e. run
for 10 seconds) I almost think it's under-powered. Like
when the stuff came all on line the power would break 
down.

The one thing that's different with ours, and that still
keeps me a little nervous, is that the cabinet and the neutral
line is at 110 V above the potential of where Geoff has his
N connection. I am afraid that there may be current running
along that path where it overloads a circuit or creates other
havoc?

Have we learned anything?

How can I debug the circuits? Do I have to open the power
& logic box or can I just measure at some vacant receptacle?
I thought DEC has built in testing receptacles, like the
covered one in the back at the breaker- and filter- box.
BTW, what should I measure there? I have seen this diagnostic
receptacle come in two shapes, square and round. The square one
has a metal cover with two screws, the round one has a 
twist off cap with a metal bracket over it. The square one
has 9 poles I think (at least.) And it seems as if there are
only three different signals on them

   TOP
  0 0 0 ---------- 110 V (1)
  0 0 0 -- neutral
  0 0 0 ---------- 110 V (2)

looks pretty simple, I wonder how anyone could do a sensible
diagnosis from this? Is there another similar thing on the
power and logic box that could help peek inside it?


thanks for you comments,
-Gunther


PS: This morning I went hunting for the L21-R20, the 5 pole,
3 phase, 120/208V, 20 A, receptacle to take the original
plug of the VAX 6000. I eventually found one at an "industrial
supply" dealer (don't bother at normal electrician's supply
stores.) But wow, this receptacle goes for $50 (fiftY)! I think
I pass on this one and use some more common 4 pole equipment
which I haven't looked for today. 


-- 
Gunther Schadow, M.D., Ph.D.                    gschadow@regenstrief.org
Medical Information Scientist      Regenstrief Institute for Health Care
Adjunct Assistent Professor        Indiana University School of Medicine
tel:1(317)630-7960                         http://aurora.regenstrief.org