AlphaStation 200 NVRAM Problem

[Robert Jarratt]

> >
> > I don't think the SROM diagnostics are going to help much because the
> > failure is in the DROM sequence, which comes after the SROM.
> 
>  But from the discussion referred I gather DROM outputs its diagnostics to
> this port too and you might be able to learn what exactly about NVRAM it
> complains.


Ah OK, so you think the DROM console also outputs to the SROM diagnostics?
I'd need to build some kind of adapter to do that. I'll have to research
this. Is there a standard part?


 Also you might be able to correct configuration, e.g. by poking at
> NVRAM or elsewhere appropriately;


Not really sure how to poke the NVRAM without the console, or is that what
you are suggesting?


> notice that the manual also suggests
> you might be able to bypass the DROM sequence and go to SRM/ARC
> directly, which might help recovery too.


I have definitely missed that bit. Which manual says this?


> 
>  It's up to you if you want to try this of course, I just thought it might
help as
> the existence of this SROM console might not be universally known.
> 
> > >  Finally the SROM console command reference is here:
> > > <http://h18000.www1.hp.com/cpq-
> > > alphaserver/technology/literature/srommini.pdf>.
> > > This manual doesn't specifically cover the Avanti, but I'd expect
> > > the user interface to be similar -- it's a low-level tool close to
> > > the CPU after
> > all.
> > >
> > >  NB on Avanti the 8kB NVRAM is separate from the TOY/NVR chip (which
> > > is a Benchmarq BQ4285, providing 114B of general storage only).
> > >
> >
> > I had already located the Benchmarq chip and found the spec to be
> > insufficient for the 8K NVRAM. The problem is, I don't know which chip
> > has the NVRAM, I have not been able to locate it and the manuals don't
tell
> me.
> > I hope it isn't one of the ASICs. I have posted a photo of the board
here:
> > http://bit.ly/1qHQnaB in case anyone can id the NVRAM.
> 
>  It is separately decoded on the flashbus (among flashROM, DROM,
> diagnostic LEDs and jumpers), so I doubt it's in an ASIC, that would be
too
> arcane.  I suspect they wanted to keep it separate from flashROM for
safety.
> 
> > If the NVRAM contents are maintained by the battery then there should
> > be a way to reset the NVRAM contents, but there does not seem to be a
> > way. I wonder if the NVRAM persists without power? The manual seems to
> > say that the TOY is battery backed, but makes no mention of the NVRAM
> > needing the battery.
> 
>  It is battery backed indeed and it sits right in the upper right hand
> corner: <http://web.mit.edu/6.111/www/s2007/datasheets/KM6264B.pdf>,
> next to the other flashbus devices, as expected -- next to the left there
is a
> pair of flashROMs (and a pair of sockets for another two of the four
> supported total), and a socketed DROM chip.  Being decoded as a DRAM
> bank they are also close to DRAM sockets.  Jumpers and LEDs are elsewhere,
> but obviously they have less strict PCB routing requirements.
> 
>  HTH,

Yes it does help! Thanks for that. At least I now know where the NVRAM
actually is. I have found some parts on Ebay, but I have no idea how to deal
with surface mount though, another research area...

Regards

Rob