> > > > 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