AlphaStation 200 NVRAM Problem
robert.jarratt at ntlworld.com
Sat Apr 23 11:19:58 CDT 2016
> > 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
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
> 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
> > I hope it isn't one of the ASICs. I have posted a photo of the board
> > 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
> arcane. I suspect they wanted to keep it separate from flashROM for
> > 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
> 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.
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...
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