[LispM] Fwd: troubleshooting nubus memory?

[Scott Burson]

Forgive me if I state the obvious, but have you reseated all the socketed
chips?  That's repair technique #1 for hardware of that era.  (In case you
don't know what I mean -- chips in sockets tend to work loose eventually
because of thermal cycling.  Reseating means to press each chip back into
its socket.)

I would think 1.6MW would be plenty to boot Lisp, though I don't recall for
sure.

-- Scott

On Sat, May 2, 2009 at 7:41 PM, r.stricklin <bear at typewritten.org> wrote:

> Folks;
>
> I have a MacIvory which has recently begun failing to cold boot LISP. I am
> pretty sure that it is due to a hardware error on the NuBus memory board.
> Does anybody here have any information or experience that will help me track
> down which is the failing component? This is my only NuBus memory board so
> my methods are somewhat limited.
>
> It's a NatSemi 8/16 board, with the full 16 MB (2.3 MW). If I remove the
> daughterboard to make it an 8 MB (1.6 MW) board, the MacIvory extension
> crashes during booting MacOS with a bus error, so either that tells me that
> the problem is on the base board or that 1.6 MW is insufficient.
>
> The FEP Test Main Memory utility spits out periods for a while, then starts
> blasting out errors starting after address 5150000 (somewhere around the 1.3
> MW mark - it disappeared off the screen too quickly for me to take more
> careful notes). The test continues spitting out errors, only limited by the
> speed of the FEP display. I lost patience after about thirty minutes; the
> test had managed to proceed as far as address 5522135 (about 0.2 MW of
> continuous errors).
>
> The XOR displayed is always the same: either 0100000000000000 or
> 0000000000000200.
>
> This should probably be enough to tell me where to look, but I don't know
> how the LISP addresses relate to the physical layout of memory devices on
> the board.
>
> Update: if I disable acceleration on the 8*24GC card, I get a much more
> reasonable result from the Test Main Memory utility. Just one message, and
> it stops:
>
> Uncorrectable memory error referencing physical 00005152530 at
> #<DTP-EVEN-PC (150 in (:INTERNAL FEP::TEST-48-BIT-MEMORY 0 #:SPLIT59854))
> 37000013002>
>   ECC Syndrome 204; Log Address 00005152530; Error Logged; Errors Lost
>   Uncorrected data: 11320002205537
>
> After several tries, the location is relatively static. Several identical
> results, one or two with closeby addresses.
>
> The error mode is the same with either of two MacIvory processors, so I'm
> reasonably confident it's not a problem with the processor itself.
>
> Thoughts? Thanks!
>
> Also - is the 8*24GC control panel known to be incompatible with the
> MacIvory software?
>
> ok
> bear
>
>
>
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