Ultimate RTC module replacement for Dallas DS1287, Benchmarq BQ3287, BQ4287 etc. 

The way of youtube, the ways of youtube..... I still have no clue, how it works :D

@@necro_ware no doubt you will find your way.

... until some rich asshole notices what's going on and buys up ALL remaining BQ3287 and BQ4287 stock to sell it to the retro geeks at crazy inflated prices ... would not be the first time ...

You are welcome! You mean how it is possible, that YT shows the video to you? You probably watched one of my other videos recently and YT decided to show you more ;)

Thank you, working daily to improve.

True, but soldering this part is not quite easy for the beginners. But the real question which bothers me is, how could it be, what did take so much time to watch this video? ;)

Supercap doesn't last long enough. It falls under 2V in just less than a week. You can extend the time using a boost-buck converter, but it's too much. I experimented with those, but eventually decided not to use them.

It's more something for the community, where one person makes a lot of them and sells the modules for a little money. Or for someone, who repairs a lot of retro hardware, like me )

Thank you! Didn't plan to give up yet, but it's up to you to spread it to the world ;)

I bought in China three times, they were all dead. Then I was tired of it and got five in Germany from a big official distributor, sold as new for 10€ each. Turned out, that it was old stock as well. One was dead on arrival, one died after 6 months, the others after a year. May be there are some new indeed out there, which you can buy, but I had no luck.

@@necro_ware here in north america you can get actually new parts from Digikey all day long, I've bought several and the date codes were never more than a year old

@@necro_ware You should make sure that the listed manufacturer is "Maxim Integrated", it seems to be the company that has taken over the production of these old Dallas Chips. I recently bought a DS12C887A+ to revive an old Pentium system, the date of manufacture printed on the chip was 50th week of 2020.

Looking forward to see your new videos:-)

Haha! This one was the funniest so far :D Thank you very much!

Przemek in tha house

I think I also have one board with mk48t02, but I'm currently not sure. Interesting idea with an MCU. I'll put it iny mind ;)

@@necro_ware: There's also no modern replacement for a DS1387 - which adds 2Kb of NVRAM in addition to the DS1287. As such, it is used by microchannel and EISA computers to hold the system configuration (notably Reply planars for PS/2s and NCR models). The DS1287 on PS/2s must be replaced with a model that doesn't modify (a Y2K fix) the "Century Byte" location.

@@IBM_Museum I forgot to mention, that this project is also compatible with DS1387. You just have to solder DS1385S ICs and you are good to go.

@@necro_ware: Heh - I see that you've added it now.

@@IBM_Museum Yes, as I said, I forgot to mention it.

guaranteed they don't last long. Happy hacking!

Which drop-in replacement did you use?

@@necro_ware i used the glitchworks one, like what lgr used on his p55t2p4

Thanks! The point of this module was to avoid the bad things about it, like solid body without a way to change the battery.

@@necro_ware yeah, but leaving the battery still accessible even after the potting, with a door or something

@@cocusar Sure, if s.o. want's the look, why not?! I prefer it like that however. Necroware inscription looks too cool to get covered, doesn't it? ;)

@@necro_ware I was thinking big, maybe you can engrave your name and model on the potting itself, like the engrave on the plastic chips :) but yeah, I agree

I wouldn't want it potted. Maybe a 3-D printed snap on cover? With his inscription of course!

Sure, if s.o. want's the look, why not. I prefer it like that. Necroware inscription looks too cool to get covered ;)

Isn't a bad idea since it could be something easily removeable to replace the battery

We will just have to make sure the Necroware logo is on the cover then!

@@wishusknight3009 Perfect

@@madson-web it is a bad idea, because the whole thing will be shut away in a PC case!!! It would be like putting lipstick on a pig to compensate for the mud.

Sorry, but currently no. I offered handful of them on ebay, but they were sold out very quickly.

I have, but unfortunately only thoughts and no steps :(

CR1225 should keep it running for 10 years

@@necro_ware I'd imagine that the PCs where the module would be used, would be disconnected from mains most of the time, which is why these batteries go empty at all. So that's why I'm having concerns.

At least, the original Dallas modules used the same IC and CR1225 internally and were specified for 10 years. Most of them ran a lot longer. But even if it would run only 5 years, now you can easily change the coin cell....

Btw. also why CR123A is not a good idea is height. The module is usually in the end of the ISA slots and it should be lower, than the slot itself, or your expansion cards will not fit.

Hi, yes, that was my first idea, but they are just too big. It is possible to put a socket for it higher, to avoid any contact between the battery and the pins, but then the whole module is too high, like the modifications, which I made before, drilling a hole. The problem is, that the RTC modules are usually somewhere in the end of an ISA slot and if the module is too high, the cards don't fit anymore. Eventually the CR1225 are also easy to find, they are not everywhere, like CR2032, but still very accessible.

Yes, I thought about that as well and even made some circuits already, but I'm unsure about the compatibility, timings etc. So far you can buy thise old stock chips, there is not a lot of sense to reinvent the wheel.... may be one day though....

Just 3d print a cover, if you want.

Thank you. Fixed the frequency details. The battery holder I will add later.

If you want to use integrated CR2023 battery, then no. But if you simply use an external battery connected to the on board header you don't need to modify anything.

@@necro_ware I see that will be the only option. Now strictly theoretically speaking (because Im really just a beginner in electronics) could I technically connect for example rechagable 3v li-ion battery to the circuit instead of the barrel battery? I guess there are no rechargable batteries of that size though and i could just as well use external one without additional work for the same effect of it dangling on wire... Anyway, the board is MSI 4109 and I have to thank you again because i wasn't able to find info for it before you showed that ultimate retro website.

@@necro_ware Ok, nevermind that. There is rechargable 3.6V lithium battery called LIR2023 which shares same dimensions as CR2023. Might that be a possible solution?

@@jirja3192 No, for li-ion batteries you need an additional circuit. If you drop it instead of a NiCd or NiMH battery you risk an explosion.

@@necro_ware Aha, ok. Thanks for your replies.

Thank you. There is no real difference for this module. The L versions (like LS/LCS) do work with Vcc 3.3V-5.5V and the E/S versions are designed for 4.7V-5.5V. Since the voltage on the old PC mainboards is 5V anyway, it doesn't matter, which IC you want to use. Only if you'd design your own low power circuit with 3.3V, then you'd have to use the L versions.

"Newer" DS1287 USED TO BE manufactured in the Philippines. They have not been manufactured at all for several years now. Benchmarq BQ3287 and BQ4287 can be modified to fit, but it's not 100% sure to be compatible on every motherboard

Well, I have to investigate about the RTC IC used there. Can you tell me, which model you are talking about? I googled for Philips CDI timekeeper and found at least 6 different variants.

@@necro_ware I'll get that to you tonight when I get off from work. My console is the philips CDi 910. I've been told it's the equivalent to the 205 console. I know the memory is 8k on mine. The newer revisions uses 32k.

Hi, yes they are compatible, but I don't sell them. Some people built them and sell on ebay, may be you can find them there, or build some yourself. They are open source, see in the video description.

There is a project site where you can ask your questions, however due to very limited time, I don't do support. Please read the documentation on the project site, may be you will find something useful there. github.com/necroware/nwX287

Thanks, just googled for the board images and looks so, yes. The notebook uses DS1287, so if you use nw3287 it should be a perfect replacement.

@@necro_ware thanks for your quick answer!

As far as I know the BQ3285LF is a SSOP-24 IC, but the nwX287 is designed for SOP-24. However even before I made nwX287 I also made another project, which I never presented in my videos. The nw12887 is a replacement for BQ3287 and similar modules (unlike nwX287, which supports also BQ4287 types), however it is designed for SSOP-24 ICs. I'm not using it much, because SSOP-24 is hard to solder by hand and takes more time, but if you have some SSOP-24 ICs you can use that one: github.com/necroware/nw12887

@@necro_ware Thank You. I was asking because is the only one that I was able to find on ebay. Do you know where to find the right one?

@@duskomarincic For example on AliExpress.

No

it's the same as DS1287, so this module should be compatible if used with BQ3285 IC.

Dito, cant find the kit set or completed module

You need BQ3285 and not BQ3287. The second one is the full Module. You can get BQ3285 very cheap from China. Die liefern auch nach Deutschland ;)

@@necro_ware oh yes, it was a typo... I meant BQ3285 - there are all about 10-13 € as well.... maybe 9 € from China + tax.

@@Ford_Prefect I don't know, it you noticed, but I live in Germany as well. The chips cost about 3€ incl. shipping if you buy from trustful sellers. If you are ready to risk, you can get 10 pack for 10€. Just don't search on Ebay only and you find plenty of them.

They are specified for 10 years in stand by. When the PC is running, the battery will not be used. If yor 486 was running a lot, it didn't use the battery a lot, so it could survive. Still, just a question of time.

You mean, like in my old video, which I referenced in this one? ;)

@@necro_ware Exactly. :)

@@PiotrK2022 the proper response is "oh, I'm sorry, silly of me to be concerned about a component that shares space with a hundred ugly components all covered in a PC case"!!!

@@squirlmy Ok, get lost hater. :)

I have another project in my repository, which uses the smaller chip as well. That one was my first project, but the chip is tiny and not many people can solder that. That's why I introduced this one. Back then the chips were at the same price, but since I open sourced this project the prices exploded. People around the world started to buy them off and sell thousands of this modules. It's kind of my fault, that those chips are now expensive :)

@@necro_ware Ok thank you for clarifying. Makes sense. I had to order the chips from Aliexpress because they were so expensive. Hopefully they work.

Just googled for it and they seem to have also a nice solution, but quite different design. They piggy back a PCB on a DIP IC and it is only designed for DS1287, as far as I see. But if you look at it without going into details, both solutions are eventually a rehash of the originals. This is how they look internally, before the manufacturer fills it with resin.

Hi Alberto, no I have still no online shop. Do you live in EU? The pin header is a usual 2,54mm round pin. Nothing special, you can get it everywhere