29 Mar
2006
29 Mar
'06
7:48 p.m.
I had written....
Good idea. The 7414 is at E45, CD1 goes in pin 9 (4a)
and out pin 8 (4y).
I'll ground the scope at pin 7 and see how the signal looks. If the issue
is bit 7 in the RTC is not setting (according to the diag), and I get a
good clock out of the schmitt trigger, I assume the next thing to check is
the pin 8 output of the flipflop the trigger drives? That seems to be
where bit 7 comes from.
On the DL11-W I was using, the BUS LTC L signal can be seen going in pin 9
of the 7414, but it doesn't come out on pin 8. Problem identified :) I then
tried two other DL11-W cards, and made sure that both of them showed the LTC
in on 9 and out clean on 8. They do. So I ran the DL11-W diag on both these
other cards, and it fails for different reasons.It prints the normal diag
startup message, followed by "01 devices under test" and the cpu halts. I
find it hard to believe both fail the same way, so I suspect something else.
Per a suggestion from another listmember, I'm going to remove all the I/O
cards, put dual grants in, and ring out the 4 bus grant lines across the SPC
slots and see if there is a break somewhere.
Jay West