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Trying to get an 11/73 CPU up and running...
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commodorejohn
Sep 26, 2012, 4:30:20 PM9/26/12
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I recently got the guts of a MicroPDP-11/73 from the recycle center -
KDJ11-AA CPU, MXV11-B serial/diagnostic/ROM/RAM card, and a couple 2MB
DataRAM memory cards, among other things. I'd like to use this stuff
to upgrade my existing 11/23+, since I didn't get the whole system it
came from. I've started off by removing all the cards from my 11/23
and dropping in the CPU and serial/ROM card - that *should* be enough
to make sure it's operational.
Unfortunately, it's not saying anything over the console serial port
(or the other one.) I've checked the settings of the serial-card
jumpers against the manual, and it looks like I've got the baud rate
set properly, so I don't think that's the problem. And the CPU must be
working in *some* capacity, since the diagnostic LEDs go through a
regular pattern: octal 3, 1, 3, 7, 4, 10, 11, 13, 14, 15, 16, pause at
16 for a few seconds, and then loop back to 7. But I can't figure out
from the MXV11 manual what these numbers represent - they may indicate
the power-on tests being performed, but why is 3 repeated, and why are
others being skipped?
One possibility is that it's not using the normal bootstrap ROM the
MXV11 manual is geared toward; the system that this was pulled from is
some kind of custom box called "MicroVIP" from U.S. Design Corp., and
it's got a custom signal-distribution board with a third serial port
labeled "Diagnostic" as well, so this might be some kind of OEM self-
test/bootloader ROM that runs its own sequence and talks on a separate
serial port that it's not finding. I'm up for getting a couple EEPROMs
and replacing the bootstrap, just to be sure, but the 11/73 firmware
files on bitsavers add up to 32KB (2x16KB,) whereas the MXV11
(according to the manual) only accepts 2x8KB ROMs.
Any idea what might be going on here? Or where I can get ROM dumps to
replace the unknown firmware with?
KDJ11-AA CPU, MXV11-B serial/diagnostic/ROM/RAM card, and a couple 2MB
DataRAM memory cards, among other things. I'd like to use this stuff
to upgrade my existing 11/23+, since I didn't get the whole system it
came from. I've started off by removing all the cards from my 11/23
and dropping in the CPU and serial/ROM card - that *should* be enough
to make sure it's operational.
Unfortunately, it's not saying anything over the console serial port
(or the other one.) I've checked the settings of the serial-card
jumpers against the manual, and it looks like I've got the baud rate
set properly, so I don't think that's the problem. And the CPU must be
working in *some* capacity, since the diagnostic LEDs go through a
regular pattern: octal 3, 1, 3, 7, 4, 10, 11, 13, 14, 15, 16, pause at
16 for a few seconds, and then loop back to 7. But I can't figure out
from the MXV11 manual what these numbers represent - they may indicate
the power-on tests being performed, but why is 3 repeated, and why are
others being skipped?
One possibility is that it's not using the normal bootstrap ROM the
MXV11 manual is geared toward; the system that this was pulled from is
some kind of custom box called "MicroVIP" from U.S. Design Corp., and
it's got a custom signal-distribution board with a third serial port
labeled "Diagnostic" as well, so this might be some kind of OEM self-
test/bootloader ROM that runs its own sequence and talks on a separate
serial port that it's not finding. I'm up for getting a couple EEPROMs
and replacing the bootstrap, just to be sure, but the 11/73 firmware
files on bitsavers add up to 32KB (2x16KB,) whereas the MXV11
(according to the manual) only accepts 2x8KB ROMs.
Any idea what might be going on here? Or where I can get ROM dumps to
replace the unknown firmware with?
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