Fun with a DWUBA

From: Gunther Schadow <gunther_at_aurora.regenstrief.org>
Date: Fri Mar 15 00:43:08 2002

Ethan Dicks wrote:


> OTOH, I did drop the T1010 card in the VAX and look for its presence on
> the bus. With the cables disconnected, the card fails self-test (Duh!)
> but when I go to read the ident register of the DWBUA (E 20000000), I
> get back FFFFFFFF, not the expected value (as documented in the manual).
> Having written VMS VAXBI drivers in the past, I can say that this is not
> good. The card "shows up" - the POST shows a "-0", so the VAXBIIC of
> the DWBUA is detected, but it's exceedingly unhappy. I am suspecting
> that the card is more fried than one chip. I'll keep working on it to
> see if the card needs a rudimentary amount of attachment to the UNIBUS
> to get far enough into its self-test to initialize the ident register,
> but I'm not hopeful about it - I think it should show the world what
> it is, even if it's unhappy.


Well, not necessarily. I remember having seen such behavior with
the KDB50 when I didn't install it quite properly. The new DWUBA is
coming along, in case you need it.


> Fortunately, I have docs for all of this. At this time, I suspect the
> M9313 UET, the DD11DK, the cables and the T1010 card. I just have to narrow
> down the list of suspects. I suppose I could drop the card in with the
> chip at risk removed and a lead hanging out so I can monitor what's
> happening on that pin. The pin itself happens to go to the outer-most
> pad on the VAXBI bus, looking at the board, it's the farthest pad
> from the VAXBIIC on the solder side. It goes diagonally in more-or-less
> a straight line to a pin of a DEC DC021C, 4 or 5, IIRC (it's not in front
> of me here). Either that pin sources a whopping amount of current
> from the DC021 and it was shorted to ground by a bad cable or a problem
> in the BA11, or somehow a very wrong voltage came from the BA11 into
> that pin. It's the only way I can see how a trace can get cooked and
> the chip melted at that pin.


What scares me about it is that you put in the new DWUBA and it
might just fry as much as the old one.


good luck,
-Gunther


-- 
Gunther Schadow, M.D., Ph.D.                    gschadow_at_regenstrief.org
Medical Information Scientist      Regenstrief Institute for Health Care
Adjunct Assistant Professor        Indiana University School of Medicine
tel:1(317)630-7960                         http://aurora.regenstrief.org
Received on Fri Mar 15 2002 - 00:43:08 GMT

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