This is the standard part I use: https://au.mouser.com/ProductDetail/PowerStor-Eaton/KR-5R5V334-R?qs=9GX7soZQXxEDr%252BE08UDVYA%3D%3D
Kindest regards, Doug Jackson em: [email protected] ph: 0414 986878 Follow my amateur radio adventures at vk1zdj.net On Sun, 17 Mar 2024 at 21:48, r cs <[email protected]> wrote: > Can you tell us more about the "supercap"? What is the part called and > does anyone know where these can be purchased? How long does the memory > last as compared with a more traditional battery? > > Thanks! > rcs > > On Sun, Mar 17, 2024 at 2:52 AM Brian White <[email protected]> wrote: > >> It should definitely at least be opened and looked at, and really >> especially in the case of a 100 vs the other models, it should just be >> preemptively recapped and new battery regardless, even if it looks perfect >> today. >> >> Because there is no getting around the passage of time. The batt and caps >> WILL leak eventually, and in both cases the fluid corrodes all the traces >> all around them, and by now the bulk of that theoretical maximum >> "eventually" time has already passed. If your machine is somehow still >> clean, then you are lucky and now is the time, not after corrosion starts. >> >> It's not a "if it aint broke" situation. >> >> I know it's not convenient and not appealing if the machine is working >> fine. >> >> In particular, the 100 (vs 102 or 200) are known to have caps that all go >> bad by now. 102 and 200 seem to be holding up better on average, as >> reported by people that do a lot of repairs. All my own machines had some >> level of corrosion started already, but that's only a few machines. >> >> They can be leaking and corroding while still looking fine from a cursory >> glance too. No bulging tops or anything. But they leak and it makes an >> invisible thin film that spreads far and wide on the surfaces of >> everything, and travels under the solder mask sometimes, and the pcb can >> sometimes look fine until you look real close and see sort of dark areas, >> and when you touch the soldermask there, it flakes up and you see the dark >> area is all corroded copper sometimes eaten all the way through. The >> machine runs perfectly with no hint of a problem right up until some trace >> finally gets the last connecting copper atom oxidized, unless one of the >> caps also goes out of spec enough to make the machine unstable. And then >> you discover it's not just one trace but a bunch all over the place. >> >> The good news is it's actually all fixable even in really bad cases. Big >> old through-hole stuff, even densely packed, is big and easy by todays >> standards. >> >> bkw >> >> On Sat, Mar 16, 2024, 11:52 PM Will Senn <[email protected]> wrote: >> >>> This sounds important. So far as I know, mine's original equipment. Do I >>> need to be worried? >>> >>> Will >>> >>> On 3/16/24 8:21 PM, Doug Jackson wrote: >>> >>> Every time I see one of those evil NiCad batteries, I replace it with a >>> 0.5F supercap. >>> >>> I have never had an issue with my M100, or with the Olivetti equivalent >>> (number escapes me at the moment) >>> >>> Having said that, the oldest would have been 8 years ago, so I don't >>> have the same 30years of experience regarding leaking characters. >>> >>> Doug >>> >>> On Sun, 17 Mar 2024, 11:44 am Brian K. White, <[email protected]> >>> wrote: >>> >>>> You can run plugged in to the wall for all normal random on/off >>>> operating times without worrying about it too much, IE, all day long >>>> for >>>> 8 to 12 hours or whatever, and for multiple days in a row, if unplugged >>>> when turned off. >>>> >>>> And you can leave it plugged in turned on or off overnight for one >>>> night >>>> to a few days. >>>> >>>> And you can even get away with exceeding those pretty badly once in a >>>> while. >>>> >>>> What you want to avoid is plugging it in and leaving it plugged in 24/7 >>>> for weeks or months or years, whether it's on or off. >>>> >>>> The harm is the charging circuit that charges the internal nicd battery >>>> soldered on the motherboard. The battery is not a lead/acid or gel cell >>>> that has a float value where it can just stay floating at a certain >>>> value forever, and the charging circuit is not a smart modern battery >>>> manager that knows how to stop charging when the battery is full, it >>>> just keeps on supplying a bit higher voltage than the the cells own >>>> voltage, and current just keeps on flowing backwards through the cell, >>>> and sooner or later this kills the battery by a couple different >>>> possible mechanisms from plain heat & pressure making it leak and cook >>>> off all the electrolyte, to things like the electrolysis process like >>>> electroplating, eating away all of one plate and building gunk up on >>>> the >>>> other. >>>> >>>> It's pretty forgiving so you don't have to be super careful. You can >>>> *mostly* never even think about it, and a normal random usage pattern >>>> will just naturally be fine. Just don't plug it in and forget about it >>>> for a year. >>>> >>>> It doesn't touch the AA's and it doesn't matter if the machine is >>>> turned >>>> on or turned off. >>>> >>>> Now that you make me run through it all like that, I realise this might >>>> finally be be an actual valid useful reason to install a supercap >>>> instead of a new nimh cell. >>>> >>>> Mostly there is no point, because both a cap and a battery will only >>>> last about the same number of years, and both will start to leak >>>> corrosive juice after about the same number of years. A cap is not >>>> harmed by being allowed to go all the way dead (which a battery is), >>>> nor >>>> by being allowed to stay dead for a long time (extra especially bad for >>>> a battery), but even a battery that has been so badly treated still >>>> supplies more standby time than a brand new perfect cap. All in all, no >>>> point. >>>> >>>> But one difference that matters, a cap should not be harmed by the >>>> crudeness of the charging circuit. A cap will just charge up and stop >>>> conducting and won't care about the charging supply at all. No current >>>> will keep flowing through the cap, no cooking or electrolysis etc. >>>> >>>> I have always been very much not in the supercap camp, but this is one >>>> real thing. >>>> >>>> -- >>>> bkw >>>> >>>> On 3/16/24 16:33, Will Senn wrote: >>>> > Wow, Brian! Super clear. Now, I want a REX# :). >>>> > >>>> > When you say that leaving it plugged in will kill the battery, do you >>>> > mean that I should run it off AA batteries most of the time and not >>>> my >>>> > 6v 200ma adapter? And the battery you're talking about killing is the >>>> > nicad on the board, right? >>>> > >>>> > Thanks, >>>> > >>>> > Will >>>> > >>>> > >>>> > On 3/16/24 3:21 PM, Brian K. White wrote: >>>> >> I summarize REX as: "An on-board software-controlled option rom >>>> >> library and ram image library." >>>> >> >>>> >> That's the shortest way I've found to say what it does, but that's >>>> not >>>> >> the same as saying what it's good for or why you want one. >>>> >> >>>> >> Because of the particular features and limitations of a M100, >>>> probably >>>> >> the single most life-improving thing you can do to one is to have >>>> >> TS-DOS in ROM. >>>> >> >>>> >> That one thing addresses a few different pain points. >>>> >> >>>> >> The biggest pain points of a M100 are: >>>> >> >>>> >> - Battery-backed ram only storage. Very little storage, and easily >>>> >> erased or corrupted, either by dead batteries or a software crash. >>>> >> >>>> >> - The way in manages machine-language software. How they all want to >>>> >> run in the same place in ram, yet the OS does not provide very much >>>> in >>>> >> the way of automatically moving programs into and out of that spot, >>>> so >>>> >> software is always clobbering other software, or you limit yourself >>>> to >>>> >> just having a single machine language app installed, or you have to >>>> >> figure out the arcane way to hack the binaries to relocate them to >>>> run >>>> >> at different addresses side by side, or you have to keep double >>>> copies >>>> >> of binaries so that the running copy can get clobbered and later >>>> >> replaced from the ram file copy... >>>> >> >>>> >> - The main rom provides no binary file transfer other than the >>>> >> cassette. And no *convenient* file transfer even for text. >>>> >> >>>> >> These things combine to make life kind of difficult. For instance >>>> you >>>> >> want some better file transfer app, but since you have no binary >>>> file >>>> >> transfer to begin with getting the file transfer app itself >>>> installed >>>> >> is a pain. Then once it's installed, it consumes precious ram, and >>>> is >>>> >> easily broken because of the way machine language apps are are run, >>>> >> and the simplest way to address that is to have a 2nd physical copy >>>> in >>>> >> ram, which uses up yet more of that precious 32k. etc. >>>> >> >>>> >> Having any tpdd client at all installed in any form makes >>>> transferring >>>> >> files a breeze, including binary files. This somewhat alleviates the >>>> >> small ram problem because you can easily put files away and get them >>>> >> back, as long as your tpdd software stays working. >>>> >> >>>> >> Even better is having a full featured tpdd client like ts-dos >>>> instead >>>> >> of teeny, and having it in rom instead of ram. >>>> >> >>>> >> That alleviates all kinds of annoyances. >>>> >> - It consumes almost no ram. >>>> >> - It doesn't require a pain in the neck bootstrap/loader process to >>>> >> get installed. >>>> >> - It isn't subject to being clobbered and needing to be reinstalled >>>> >> because of some other software writing over it or crashing. >>>> >> - It isn't lost after a hard reset or dead batteries. >>>> >> >>>> >> With TS-DOS in rom, you can pick up a totally dead machine, or >>>> totally >>>> >> kill your machine with a hard reset on purpose, or suffer a total >>>> ram >>>> >> corruption from buggy software, and with just "CALL 63012" you are >>>> up >>>> >> and running again, connect to a computer and pull down files. >>>> >> >>>> >> But even though this makes a lot of things a lot better, this still >>>> >> needs a computer and serial cable. The tpdd client just makes it so >>>> >> that you can effortlessly connect to a pc and move files back & >>>> forth, >>>> >> and having it in rom just means you can effortlessly always have the >>>> >> tpdd client regardless of crashes or dead batteries. >>>> >> >>>> >> That still leaves a couple things that could be better: >>>> >> - If you had a plain ts-dos option rom, it means you can't use any >>>> >> other option rom because the single socket is occupied already by >>>> ts-dos. >>>> >> - You still need a serial cable and pc (or a real tpdd drive or a >>>> >> Backpack or PDDuino) to actually get the files from somewhere / put >>>> >> them somewhere. >>>> >> >>>> >> REX gives you ts-dos in rom just for starters. It gives you ts-dos >>>> in >>>> >> rom which just that right there alleviates several things above, but >>>> >> also: >>>> >> >>>> >> - all other options roms besides ts-dos >>>> >> - full ram image backups >>>> >> - all on-device self-contained with no computer or serial cable >>>> needed >>>> >> (after initial loading) >>>> >> - impervious to dead batteries or resets or crashes >>>> >> >>>> >> And although you do need a computer to install option rom images >>>> onto >>>> >> the rex one time, ts-dos in particular is pre-installed, so that >>>> >> single most-needed one never needs even the initial one-time install >>>> >> from a computer. Only all the other roms need to be loaded from a pc >>>> >> once. And the loading process is easy, because REXMGR uses tpdd >>>> >> protocol internally to pull the rom images from a pc. No >>>> >> bootstrapper/loader procedure. >>>> >> >>>> >> The other option roms give you mostly a few different office >>>> software >>>> >> kits, ie spreadsheets and word processors, and a few other things >>>> like >>>> >> there is a FORTH rom and an assembler/debugger/renumberer. >>>> >> >>>> >> The ram image backups give you essentially more copies of 32k ram. >>>> It >>>> >> helps a few different ways: >>>> >> - you can physically hold more than 32k of apps or data. >>>> >> - you can recover from a dead battery or reset or corrupted ram from >>>> >> crashed software by restoring a ram image. >>>> >> >>>> >> There are something like 30 or so available slots, and each slot can >>>> >> be either an option rom or a ram image. That's a lot. >>>> >> >>>> >> All without a computer. In the coffee shop, on the train etc, just >>>> >> recover from dead zero in a few seconds. Just "Call 63012" and away >>>> >> you go, all interactive app and menu driven after that. >>>> >> >>>> >> So that is why you want a REX of any stripe, REX Classic, REX#, or >>>> >> REXCPM. >>>> >> >>>> >> Now for REXCPM in particular.... >>>> >> >>>> >> Those particular advantages are something the REXCPM is less good >>>> for. >>>> >> >>>> >> REXCPM does give you all of that, but only as long as the M100 >>>> >> internal battery is not dead and the REXCPM and bus adapter board >>>> >> remain installed in both sockets. >>>> >> >>>> >> You can recover from software crashes that scramble the ram, and >>>> from >>>> >> intentional hard resets that wipe all ram (ctrl-break-reset), but >>>> not >>>> >> from dead batteries or switching off the memory power switch on the >>>> >> bottom for more than a few minutes, or removing the device from the >>>> >> m100 for more than a few minutes. >>>> >> >>>> >> If the M100 internal battery runs out, or you uninstall it for more >>>> >> than a few minutes (you do get a pretty good grace period of several >>>> >> minutes, maybe even over 10 minutes) then you have to reload the >>>> >> REXCPM from scratch as you just experienced. If you had a REX >>>> Classic >>>> >> or REX# instead of REXCPM, all you would have done is type "call >>>> >> 63012" and you'd be all back up & running. No pc, no "37 easy >>>> steps". >>>> >> Done. And to remember "call 63012" just write it on a sticker or >>>> >> label-maker on the bottom. Put it on the underside of the option rom >>>> >> or battery cover if you want to hide it but then you have to at >>>> least >>>> >> remember that it's there. >>>> >> >>>> >> I did make a "UPS" for REXCPM that should keep it alive for a few >>>> >> years, but it's pretty involved to build and ultimately hard to >>>> justify. >>>> >> I don't pretend it's practical for most people, but it does work and >>>> >> exists. >>>> >> https://github.com/bkw777/REXCPM_UPS >>>> >> >>>> >> You have to buy the parts from digikey or mouser etc, order pcbs >>>> from >>>> >> elecrow or oshpark etc, and then it's a pretty fiddly soldering job, >>>> >> and it ends up costing as much or more than the rexcpm itself just >>>> to >>>> >> give it a battery. And for all that, I think I only estimated 6 >>>> months >>>> >> per cell x 4 cells = 2 years, but that's after the M100's own >>>> >> batteries run out, and if you have fresh alkaline AA's and a charged >>>> >> internal battery, the M100 itself can last anywhere from a few >>>> months >>>> >> to a year. So maybe up to 3 years? >>>> >> >>>> >> A better long-term solution would be a keeper. You remove the rexcpm >>>> >> and plug it in to something with socket and a big battery. But that >>>> >> doesn't help with one that's installed in a machine. You'd need to >>>> >> remove it from the machine to put it in the keeper. Plus the molex >>>> >> sockets are no longer made. There are a few around available still >>>> but >>>> >> this would be a wasteful way to use one up instead of keeping them >>>> to >>>> >> repair machines. Really, for the long term like over 5 years, it's >>>> >> probably more practical to just let it die and reload it. With a >>>> >> convenient bootstrapper and tpdd server on a pc, it only takes a few >>>> >> minutes to reload a rexcpm from scratch. It's several steps that >>>> >> requires a cheat sheet to follow, but none are very difficult or >>>> long. >>>> >> The hard part is just deciphering the original directions to figure >>>> >> out what actually are the steps you need to do. >>>> >> >>>> >> So all in all, I'm not sure how necessary the ups is. It's probably >>>> >> more practical to just do 2 things to live a happy life with a >>>> REXCPM: >>>> >> >>>> >> 1 - Keep it installed in a machine. And keep that machine charged. >>>> >> (Unfortunately, you can't just lave the machine plugged in to the >>>> wall >>>> >> 24/7 for months, that will cook the internal battery.) >>>> >> >>>> >> 2 - Get good at reinstalling it. It's several steps, but it's >>>> possible >>>> >> to write a little cheat sheet that is easier to follow than the full >>>> >> original documentation. And none of the steps are very difficult or >>>> >> long. You don't even need the cheat sheet after a few runs through. >>>> >> >>>> >> If you aren't specifically wanting to run CP/M then I always say a >>>> >> REX# is far more practical. REX# is an nvram device that acts like a >>>> rom. >>>> >> >>>> >> Instead of ever needing to recover the REX, the REX is what recovers >>>> >> your M100. >>>> >> >>>> > >>>> >>>> -- >>>> bkw >>>> >>>> >>> > > -- > *Níl aon tinteán mar do thinteán féin. *[Irish Gaelic] > (There is no fireside like your own fireside.) > > >
