DS12887 drop-in replacement

Discussion about old PC hardware.

Re: Possible DS12887 drop-in replacement

Postby Maeslin » 2014-4-24 @ 20:37

Unknown, the print shop I went with doesn't do soldering at all. (OSHPark)

Besides, the circuit is fairly simple. Shouldn't take more than 10-15 minutes per module taking it easy.
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Re: Possible DS12887 drop-in replacement

Postby SquallStrife » 2014-4-24 @ 22:40

feipoa wrote:Zero cost? How can I resist. Put me down for 1.


If there's room for one more, my hand is raised! ;)
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Re: Possible DS12887 drop-in replacement

Postby Maeslin » 2014-5-16 @ 21:28

Another little update:

I assembled 4 of the modules. 2 with 'authentic' DS12885s, 2 with chips sourced from alibaba so authenticity is debateable. I've programmed all 4 with different dates (same date, with 1-year offset) and disconnected them from the system. They'll be kept in storage for a few more weeks then tested again to check accuracy and battery level. I suspect the alibaba chips may be rebadged TI BQ3285, which are direct drop-in replacements for the 12885 but much cheaper. Initial testing shows no difference whatsoever in behavior and battery drain between the DS12885s and the 'rebadged' after a two week period and accuracy is well within the margin of error.

If accuracy and battery level prove satisfactory on both authentic and 'uncertain' chips, I will ship the two freebies to feipoa and tr3vor. When they can confirm reception and satisfactory function, I will begin further assembly and distribution.

Pics will follow early next week.
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Re: Possible DS12887 drop-in replacement

Postby feipoa » 2014-5-17 @ 04:06

Looking forward to it!
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Re: Possible DS12887 drop-in replacement

Postby Tr3vor42532 » 2014-5-17 @ 06:08

Nice, glad to see this project getting somewhere. This will be much nicer than a maybe half dead RTC you buy from ebay. :P
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Re: Possible DS12887 drop-in replacement

Postby Maeslin » 2014-5-17 @ 10:22

I may even include the battery since I got a good pack of them, but on those I can't promise anything about the condition. Besides, having a replaceable battery is the whole point of this project. ;)

Also, if some would prefer making it themselves, here's the PCB and where to order it. There's really not much of a need for schematics considering the part count.

http://oshpark.com/shared_projects/DgExxcyH
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Re: Possible DS12887 drop-in replacement

Postby dacow » 2014-5-28 @ 02:06

How coincidental I saw this post, I just got a system with a dead ODIN RTC on it. Can't wait to see how this turns out because I would definitely be in for one or two :)
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Re: Possible DS12887 drop-in replacement

Postby Auzner » 2014-5-28 @ 15:33

Maeslin, are you still selling a kit?
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Re: Possible DS12887 drop-in replacement

Postby Maeslin » 2014-5-28 @ 21:04

Not yet, waiting 'till early next week to see if the ones I made so far still have their timekeeping after a month unsocketed, then shipping two to some users so they can test it themselves. When they report the all green I'll start making more and selling.
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Re: Possible DS12887 drop-in replacement

Postby retrofanatic » 2014-5-28 @ 21:16

This is awesome...I am also looking forward to buying one of these...I will want one for an old NEC computer I have with a dreaded RTC on it. It's not dead yet, but I'm sure it will happen soon, and then I'll be ready with one of these beauties.
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Re: Possible DS12887 drop-in replacement

Postby Maeslin » 2014-5-28 @ 23:57

I'll probably even be able to include a battery (packaged separately) too! Seems CR1216/1220/1225s can be somewhat hard to find in some areas.

Also, pics tomorrow.

Might also accept a trade for a pair of (or even a single) confirmed working 64MB (so 128MB total) 72-pin SIMMs, parity or no, EDO preferred. Attempting to diagnose a single-board computer that claims to be limited to 32MB SIMMs and I have no way to know if it's just incompatibility with the (not sure if working correctly) sticks I have right now, which should be 64MB but are only detected as 32. (If someone has the know-how to tweak a bios to add support, even better).
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Re: Possible DS12887 drop-in replacement

Postby Maeslin » 2014-5-30 @ 00:37

Aaaand pic!
Image

Yes, they're slightly smaller and narrower than the original DS12887. :D
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Re: Possible DS12887 drop-in replacement

Postby SquallStrife » 2014-5-30 @ 02:36

Oooer, looking good!

Man, I can't get enough of that OSHPark purple PCB...
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Re: Possible DS12887 drop-in replacement

Postby dacow » 2014-5-30 @ 07:41

Looking pretty sexy! where's the "Buy Now" button? :)
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Re: Possible DS12887 drop-in replacement

Postby feipoa » 2014-5-30 @ 08:12

There was a "free" button originally. I was surprised that more people didn't sign up for that when it was available.
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Re: Possible DS12887 drop-in replacement

Postby dacow » 2014-5-30 @ 08:48

feipoa wrote:I was surprised that more people didn't sign up


For me personally I didn't have any need for it until getting a P166 a few days ago with a dead ODIN :) Rest of my mobo's had buton cell batteries or none at all.
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Re: Possible DS12887 drop-in replacement

Postby Auzner » 2014-5-30 @ 20:09

Pretty much anybody who actively deals with old computers is going to want to buy these. It's just a matter of spreading the word.
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Re: Possible DS12887 drop-in replacement

Postby feipoa » 2014-5-30 @ 21:55

Now only if making a drop-in PS/2 mouse port for the KBC was so simple...
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Re: Possible DS12887 drop-in replacement

Postby KT7AGuy » 2014-5-30 @ 22:10

Hi!

I'll definitely order at least one when you're ready to ship.

I've got an old Tyan S1563S that has one of those Dallas RTC battery/chips. A few years ago, it died and I was forced to contemplate my options. At the time, I found these two websites about "fixing" the problem:

http://www.mcamafia.de/mcapage0/dsrework.htm

http://www.walshcomptech.com/ps2/dallasrework.html

I didn't feel like getting creative with my dremel tool, so I ended up just buying a new one. I saved the old dead one thinking that one day I would make the necessary CR2032 mods to it, but I never got around to it.

I would much prefer to purchase one of yours. I look forward to it!

Thanks!
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Re: Possible DS12887 drop-in replacement

Postby Tr3vor42532 » 2014-6-21 @ 18:07

So I got the test unit and installed in in my cousin's 486 about 6 days ago and it works perfectly so far.
Image Image

These are definitely a good idea. Works a lot better than our modi-fried dallas chip we had in there that drained the battery every couple days for some reason.

Ugh, he needs a vlb video card :P
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