On 05/26/2019 10:44 AM, Jon Elson via cctalk wrote:
  On 05/26/2019 12:13 AM, Mister PDP via cctalk wrote:
  Ok, small update. My M8043 (DLV11-J) just arrived
today.
 It seemed in good
 condition so I confirmed it was set up correctly (9.6k
 baud and console on
 J3), built a serial cable from the information provided
 on gunkies, and put
 it into my system. Sadly, it behaves exactly how it did
 with the M8017. No
 output, no activity on the BRPLY line. I have a hard time
 imagining that
 both my M8017 and my M8043 are bad, but it could still be
 possible.
 
 Well, if just ONE address line driver on the CPU has gone
 bad (or a short in the backplane) it could prevent the DLV
 from recognizing the address.  If there are any other
 boards in the system, take them out.  Maybe even the
 memory boards, and try to read/write the DLV addrsss from
 the console.  (Oh, maybe that's the problem, you don't
 have the full programmer's console on this machine.)
 
Oh, DLV means Q-bus, so there isn't much choice EXCEPT
serial console, is there?
Yeah, when the serial console doesn't work, you've got a
problem. You could check each addr/data line to see that it
wiggles.  If it doesn't wiggle, then you can see if the
state it is in makes sense. Obviously, somewhere in the
serial console routine, it should be addressing the serial
console, so every line should at some point be in the state
to select the console CSR.
A logic analyzer set up to read out the bus would be a good
tool at this point.
Jon