After some very minor cleanup and front panel fixing, the DG1230 seems to spring to life.
I can deposit and examine different values from all four cpu registers, as well as small
random ranges of memory. I've been skimming some of the DG docs I have, but I am
coming up short on knowledge on a few points and was wondering if someone could shed light
on any of these items or better yet, direct me to the appropriate manual that I can't
seem to find.
1) In DEC & HP documentation, I can find a fair number of "front panel
dittys" to perform basic tests in the absence of I/O devices. I can find no such
short programs for the DG1200. Before I attach an I/O device (CRT, Cassette, or paper
tape) I'd sure like to feel more confident that the cpu is on fairly solid ground.
Unless someone knows of some docs on short front panel test programs, I'll just write
a few short "copy range of memory from A to B, etc." programs myself and hand
assemble them.
2) At the bottom of the backlane are several small pin connectors - P5, P6, P7, P8, and
P9. Going from memory, but they are something like 2 rows of about 10 pins per row for
each P connector. I can't seem to find where these are documented. Can someone point
me to the right manual? They don't even show up on the backplane diagrams I have.
3) On most of my DG12xx cpu's, the backplanes don't have extra wiring, other than
what is obviously going to a device. But on this one, Pin 10 of backplane connectors 2
through 12 is daisychained. I believe the signal is "VINH". I can't seem to
find documentation on this. I'm guessing it has to do with allowing (or disallowing)
memory cards in slots other than slot 2, but I'd like some better understanding as to
when and when not this jumper set should be present.
4) Again, on most of my DG12xx boxes, the backplane has nothing other than I/O
connections. But on this one, pin 96 (intp in) slot five is wrapped to pin 95 slot 16
(intp out). Likewise pin 94 (dhcp in) is wrapped to pin 93 slot 16 (dhcp out). I do have
some idea what this is for, but I'd like a better understanding as to when and when
not this jumper should be present. This has got to be documented/explained somewhere, but
I sure can't find a discussion of it. Thoughts? I'm guessing this jumper is only
required to get DHCP to the upper I/O card section on the "jumbo" version?
Thanks in advance for any thoughts!
Jay