Re: DECstation 2100: power trouble?

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

> Have built-in console memory tests (e.g. `t a' I mentioned
> previously) never shown any failures?

I shut it down and pulled all RAM except slots 1 and 2.  It failed to
POST, getting stuck on test 2.  After looking up which test 2 was, I
fixed the microtransceiver's connection and it passed POST.  It
netbooted to single-user without issue - but 4M of RAM is not very
much; it said "avail memory = 1184 KB".  But that's not enough RAM to
do anything useful.

So I put back another 6 sticks, bringing it to 16M (slots 1-8
populated).

As for t a....

>> t a
-009-00 wrt vdac map w/ inc pat
-009-00 chk vdac map w/ pat
-00a-00 wrt vdac ovrly w/ inc pat
-00a-00 chk vdac ovrly w/ pat
-03c-00 chk pcc forc mod
-03d-00 chk pcc forc mod
-03e-00 chk pcc forc mod
-03f-00 chk pcc forc mod
-03f-00 chk pcc enb mod
-041-00 chk pcc enb mod
-042-00 chk pcc enb mod
-043-00 chk pcc enb mod
-01c-00 dz ln 00 int rx/tx lpback tst
-01c-00 dz ln 01 int rx/tx lpback tst
-01c-00 dz ln 02 int rx/tx lpback tst
-01c-00 dz ln 03 int rx/tx lpback tst
-01d-00 dz silo alarm tst
-001-00 chk data cache ram w/ pats
-002-00 chk instruction cache ram w/ pats
-003-00 cache seg tst
-004-00 chk inst cache
-005-00 i cache tag tst
-005-01 d cache tag tst
-005-02 i cache tag parity tst
-005-03 d cache tag parity tst
-005-04 i cache data parity tst
-005-05 d cache data parity tst
-005-06 i cache valid bit tst
-005-07 d cache valid bit tst
-017-00 fpu tst
-059-00 wb err addr tst
-010-00 wrt nv ram  w/ 00000055
-010-00 chk nv ram w/ 00000055
-011-00 wrt nv ram  w/ 000000aa
-011-00 chk nv ram w/ 000000aa
-012-00 wrt nv ram w/ inc pat
-012-00 chk nv ram w/ pat
-057-00 csr tst
-05e-00 tlb tst
-05a-00 mse tst
-05d-00 esar tst
-022-00 wrt nram w/ 0000
-022-00 chk nram w/ 0000
-023-00 wrt nram w/ 5555
-023-00 chk nram w/ 5555
-024-00 wrt nram w/ aaaa
-024-00 chk nram w/ aaaa
-025-00 wrt nram w/ ffff
-025-00 chk nram w/ ffff
-026-00 wrt nram w/ inc pat
-026-00 chk nram w/ pat
-04f-00 lance CSR tst
-050-00 lance Intrnl LB tst
-051-00 lance Extrnl LB tst
-052-00 lance CRC err detect tst
-053-00 lance Promiscuous mode rx tst
-054-00 lance Coll detect tst
-055-00 lance Multicast rx tst
-056-00 lance IRQ tst
-02a-00 wrt dram w/ 0000
-02a-00 chk dram w/ 0000
-02b-00 wrt dram w/ 5555
-02b-00 chk dram w/ 5555
-02c-00 wrt dram w/ aaaa
-02c-00 chk dram w/ aaaa
-02d-00 wrt dram w/ ffff
-02d-00 chk dram w/ ffff
-02e-00 wrt dram w/ inc pat
-02e-00 chk dram w/ pat
-047-01 SII bfr adr tst

-048-01 sii tgt ilpbk 
-048-02 tgtst:  STLP <-  4
-048-03 tgtst: bldg obnd cmd/dta
-048-04 tgtst: set lpbk md
-048-05 tgtst:  sel + pen
-048-06 tgtst: id <-  7
-048-07 tgtst: en dssi md
-048-08 tgtst: dev 0 sel dev 7
-048-09 tgtst: dsel
-048-0a tgtst: snd cmd[0]
-048-0a tgtst: snd cmd[1]
-048-0a tgtst: snd cmd[2]
-048-0a tgtst: snd cmd[3]
-048-0a tgtst: snd cmd[4]
-048-0a tgtst: snd cmd[5]
-048-0a tgtst: snd cmd[6]
-048-0b tgtst: snd dta[0]
-048-0b tgtst: snd dta[1]
-048-0b tgtst: snd dta[2]
-048-0b tgtst: snd dta[3]
-048-0b tgtst: snd dta[4]
-048-0b tgtst: snd dta[5]
-048-0b tgtst: snd dta[6]
-048-0b tgtst: snd dta[7]
-048-0b tgtst: snd dta[8]
-048-0b tgtst: snd dta[9]
-048-0b tgtst: snd dta[10]
-048-0c tgtst: rcv sts
-048-0d tgtst: chk bfr sts
-048-0e tgtst: chk cmd blk
-048-0f tgtst: chk dta bytes
-048-10 TGTST: OK

-049-01 sii ini ilpbk tst
-049-02 initst: bld obnd pkt ad = bb000020
-049-03 initst: ILP <-  4
-049-04 initst: set lpbk md
-049-05 initst:  sel + pen 
-049-06 initst: ID <-  7
-049-07 initst: arb wina
-049-08 initst: dssi md
-049-09 initst: BSYa + CDa
-049-0a initst: rcv cmd[0]
-049-0a initst: rcv cmd[1]
-049-0a initst: rcv cmd[2]
-049-0a initst: rcv cmd[3]
-049-0a initst: rcv cmd[4]
-049-0a initst: rcv cmd[5]
-049-0a initst: rcv cmd[6]
-049-0b initst: -> dta phse
-049-0c initst: rcv dta[0]
-049-0c initst: rcv dta[1]
-049-0c initst: rcv dta[2]
-049-0c initst: rcv dta[3]
-049-0c initst: rcv dta[4]
-049-0c initst: rcv dta[5]
-049-0c initst: rcv dta[6]
-049-0c initst: rcv dta[7]
-049-0c initst: rcv dta[8]
-049-0c initst: rcv dta[9]
-049-0c initst: rcv dta[10]
-049-12 initst: -> sts phse
-049-0d initst: dscon
-049-0e initst: chk bfr sts
-049-0f initst: chk CSTAT
-049-10 initst: intrd
-049-11 INITST: OK

-04c-01 SCSI scndev

-04c-02 No SCSI dev 
>> 

which looks happy to me (there is in fact nothing on the SCSI bus).

> I think a marginal PSU might cause memory errors at load spikes.

Fair point.  Running with 16M instead of 24M should reduce PSU load
marginally.

> At least replacing output filter capacitors ought to cause no
> regression.

True.  I'l pull the PSU at some point, look at what it's got for caps,
and see if I've got suitable replacements on hand.  I may need to order
some....

I should also put my multimeter in the PSU lines and see what it says
for both DC and AC measurements, the former for nominal voltage and the
latter for ripple.

It was working OK for me, but I tried to set up a fan to cool the CPU
and FPU and apparently the power supply didn't like that.  Now it's
getting stuck at EF on the lights again, even with the fan
disconnected.  I suspect I may need to do the power supply
investigations.

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