Re: DECstation 2100: power trouble?

[Mouse <mouse%Rodents-Montreal.ORG@localhost>]

So I finally gavea up on the 2100 and put the other 10 sticks of RAM
back in.  Just on the chance, I then turned in on.  It promptly passed
POST and netbooted!  Perhaps I was wrong about which slots were bank 0;
I figured they were the two closest to the front of the machine, given
the direction the RAM has to lean to be put into or taken out of the
sockets (since those two slots are the last ones to be removed and thus
first to be installed).

So I started a (diskless) rebuild of the 1.4T world.  A little over
thirteen minutes in, though, while still doing the `make cleandir'
step, I got (the leading "# " is the shell prompt the console was
sitting at)

# trap: bus error (load or store) in kernel mode
status=0x8fc34, cause=0x9000001c, epc=0x8003055c, vaddr=0xc0034800
pid=1590 cmd=sh usp=0x7ffff9f8 ksp=0xc251b778
Stopped in sh at        0x8003055c:     beq     a2,zero,0x8003057c
                bdslot: 0x80030560:     lbu     v0,0(a0)
db> reboot
syncing disks... done
trap: bus error (load or store) in kernel mode
status=0x8ff14, cause=0x1c, epc=0x80199390, vaddr=0xc0c173c4
pid=1590 cmd=sh usp=0x7ffff9f8 ksp=0xc251b2b0
Stopped in sh at        0x80199390:     lw      v1,0(s2)
db> reboot
syncing disks... done

It then hung there.  I coaxed it into passing selftest again, but then
booting failed:

NetBSD 1.4T (kernbuild) #4: Sun Oct 31 17:30:43 EST 2021
    root@:/root/kernbuild
DECstation 2100 (PMAX)
total memory = 24576 KB
avail memory = 20124 KB
using 332 buffers containing 1328 KB of memory
mainbus0 (root)
cpu0 at mainbus0
cpu0: MIPS R3000 CPU Rev. 2.0 with MIPS R3010 FPC Rev. 2.0
cpu0: 64KB Instruction, 64KB Data, direct mapped cache
ibus0 at mainbus0
pm0 at ibus0 addr 0xfc00000: 1024x864x1
dc0 at ibus0 addr 0x1c000000
le0 at ibus0 addr 0x18000000: address 08:00:2b:14:8c:7e
le0: 32 receive buffers, 8 transmit buffers
le0: supplying EUI64: 08:00:2b:ff:fe:14:8c:7e
sii0 at ibus0 addr 0x1a000000: target 6
mcclock0 at ibus0 addr 0x1d000000: mc146818 or compatible
Beginning old-style SCSI device autoconfiguration
trap: bus error (load or store) in kernel mode
status=0x8ff04, cause=0x1c, epc=0x801a6dc8, vaddr=0xc0002c48
pid=0 cmd=swapper usp=0x0 ksp=0x8025fde8
Stopped in swapper at   0x801a6dc8:     lw      v1,24(a1)
db> 

So I put the machine back together (I was running it with the cover and
disk-mounting plate off, for better cooling) and have stopped fussing
with it for now; I'm finding I don't have the frustration tolerance
these days to handle dealing with broken hardware, especially subtly
broken hardware.

:-(

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