21 Feb
2008
21 Feb
'08
2:59 p.m.
On 21 Feb 2008 at 12:44, Tim Riker wrote:
Agreed. The question is why. :)
The microcode sets overflow on at the start of the loader routine and turns
it off after verifying the starting memory location and the select code.
These are only these two jumps out of the routine with overflow set.
If P is set as expected by IBL (i.e., 077700 for 32K), then the select code
= 10 check is failing. Perhaps the ribbon cable from
the front panel to
the CPU is bad.
If P is set to 177700 (bit 15 on), then the memory check is failing.
FYI: I'm started taking notes here:
http://rikers.org/wiki/HardwareNotes
Your list shows slot 118 open. The HP installation manual recommends that
the memory controller go in 118 and the memory cards follow above in the
cage.
You might try reseating the ribbon cable that connects the left-side edge
connectors of the memory cards and the controller card. (The right side
connectors are open.) Also, the ribbon cable that attaches to the DCPC
card.
Note that the memory controller must be strapped for an M-Series; if it's
strapped for an E-Series, the timing will be off.
-- Dave