28 Mar
2018
28 Mar
'18
3:59 p.m.
Hi Peter,
However, they do not provide the SROM> prompt or
accept mini console commands
unless a I engineer another fault condition such as by pulling out one of the
memory risers. I wonder if there is a jumper to enable mini console commands
to be accepted without doing this? Looking around the system board, I see a
pair of jumper pins labelled J9 hidden under the I/O board which looks like it
could do this. Unfortunately, while there is legend on the PCB indicating the
function of all other jumpers, there is none for J9 and it is not mentioned in
the manual either.
"DEC 3000 Models 600/600S AXP and 800/800S AXP Service Information",
Order Number: EK-FLSPC-SV. A01 (flspcsva.pdf) seems to indicate on page
2-2 that the SROM console jumper is one in position 0 among the SROM
jumpers whose location is shown in the figure on that page. I have
checked my /700 (which is the same as the /600 except for a faster CPU)
and this is also marked J8 on the PCB.
The 600 machines have a socketed 27C512 EPROM. I
assume this must be the SROM
(although I can't see what is serial about it) as the machines fail to update
the diagnostic LEDs or write to the mini console if it is removed. I dumped
the two EPROMs and compared them and they are identical. However, I can't see
any ASCII strings in them. Perhaps the bits are not used in the standard
order? The manual suggests that there are 8 different 8KB SROM images present
and those other than the "standard" one may be used for testing and
diagnostics
by setting jumpers. Unfortunatly, there is no further information about these
images.
The location of the SROM chip is also shown in the figure on page 2-2.
The format of the headers in the SYSROM and IOROM do
not exactly match the
format given in the manual but they are "close". I wonder if this might
be my problem or if the manual is incorrect. If anyone else has a 3000 600,
could they take a peek at their SYSROM and maybe we could compare notes?
I could check my /700 with SRM. What would you like me to look at?
Hope this helps. Good luck with your fault debugging.
Maciej