Fun with a DWUBA

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.

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.