On Fri, Jul 7, 2017 at 7:35 PM, Mike Stein <[email protected]> wrote: > Hi Frank; you must be on just about every vintage computer list out there ;-)
nah, not really, just the ones about the old computers that I have (a few indeed). > > Any chance you'd release the PCB files for those boards to the unwashed > public? well, no problem for me, just contact me via private email. However, I'm not responsible for anything that happens with the products of my files. I test all modules with my dedicated setup and also these modules need to be washed after manufacture because some flux residues have enough conductivity when damp to add a few uA of leakage. Best regards Frank IZ8DWF > ----- Original Message ----- > From: "Francesco Messineo" <[email protected]> > To: <[email protected]> > Sent: Thursday, July 06, 2017 3:13 AM > Subject: Re: [M100] NEC 8201A Ram > > >> Hello, >> I'm new to this list, I've been just reading for a while. >> >> On Thu, Jul 6, 2017 at 6:14 AM, Brian White <[email protected]> wrote: >>> 102 is easy. 100 is not so easy. >>> >>> There was a guy in Romania selling NEC branded modules dirt cheap last year >>> but those are gone now. Or at least they're not on ebay any more. They >>> weren't labeled for model-100, I just found them by searching for the main >>> chip number, took a chance, and they turned out to not only fit but also >>> work. Maybe I should save his info before I lose track of it, in case he >>> does still have some. >>> >>> Maybe modules for 100 are another good candidate for an open OSH Park design >>> that people can build new on-demand. The basic wiring for adapting to some >>> more common chips is well documented. >>> >> >> I've made many RAM modules replacement for the Olivetti M10 (and all >> the other compatibles) for some friends that asked for batches of >> them. >> Here's how one module looks like inside my M10: >> >> https://www.dropbox.com/s/iwyjg7p22c8xt5t/IMG_1484.JPG?dl=0 >> >> I've developed also a custom setup to test the modules outside the M10 >> (socket was getting >> worn out during my prototype tests): >> >> https://www.dropbox.com/s/38q01n8gckuz3of/IMG_1906.JPG?dl=0 >> >> And here's one of the batches I've made for an italian collector: >> >> https://www.dropbox.com/s/c5zes6lgevdkz2n/IMG_0266.JPG?dl=0 >> >> And here's another version of the module with slightly different logic >> to use different SRAM >> chips: >> >> https://www.dropbox.com/s/1p9tz1jgirbfaee/IMG_1601.JPG?dl=0 >> >> The test setup include different address and block tests and also a >> standby current measurement as these modules must not draw more than >> 2-4 uA during standby conditions to allow the memory battery backup >> last a reasonable amount of time. >> Most of the modules settle to much less than 1 uA standby current. A >> few ones went up to 1 uA. The original modules can draw up to 4 uA in >> standby mode. >> >> Best regards >> Frank IZ8DWF >> >>> -- >>> bkw >>> >>> On Jul 5, 2017 10:29 AM, "Jason Benson" <[email protected]> wrote: >>>> >>>> I want to fix the 8201A but I haven't had any luck yet determining the >>>> cause of the trouble. (see other thread about internal NiCd batteries) >>>> >>>> On Wed, Jul 5, 2017 at 10:05 AM, Josh Malone <[email protected]> >>>> wrote: >>>>> >>>>> What happened to the 8201A? It might be more beneficial to just repair >>>>> that. >>>>> >>>>> I can tell you from experience that SRAMs for the model-T are easy to >>>>> come by. (I recently replaced a RAM chip in my 102 w/ parts from ebay) No >>>>> reason to scavenge other machines for these parts. >>>>> >>>>> -Josh >>>>> >>>>> On Wed, Jul 5, 2017 at 9:19 AM, Jason Benson <[email protected]> >>>>> wrote: >>>>>> >>>>>> My 8201A that died the first time I tried to use it has a full set of >>>>>> ram expansions. Are those ram expansions usable in any of the other >>>>>> computers from the M100 family? I imagine the NEC PC 8300 probably uses >>>>>> the >>>>>> same chips, but probably not the M100/102. >>>>>> -Jason >>>>> >>>>> >>>> >>>
