I'll try to find time to get a 486 setup in the next couple of weeks to verify mine.

Glad to hear it works! For a 'proper' test, leave the PSU unplugged for a few days/weeks. If it keeps its time, it's perfect.

Actually, noticed you had an AT PSU. Nevermind, those don't have standby voltage.

Damn that purple module looks good. 😁

tbh, I'm more interested in that it makes the computer works than the time 😜

but yeah, I'll do that, leave it off for a week or two and turn it back on.

I have put the DS12887 into my IBM 5x86-133 system and will report back in a month as to how well it is keeping time. For the short few hours I have tested it thus far, the unit properly saves BIOS settings and keeps time.

Perfect! I already have another 10 assembled, 2 of which are tested. I'll start working on those and, once they're tested, start putting them up on ebay/amibay since we're not really supposed to sell stuff on this forum (unless I'm mistaken) :p

No trouble with getting the battery in/out?

I only put the battery in.

How much do you think these can go for? After shipping and such, a brand new RTC from Maxim is around $22 USD.

It'd be $15 + shipping. Unfortunately shipping is the real killer here, I don't have the sweet enterprise-scale deals that Maxim has. Regular untracked snail-mail to the US would be between $3.50 and $5.00, small parcel would be $8 and up. Anything tracked and shipping is actually more expensive than the package.

Seems reasonable considering the time put in and the continuing time required to solder.

I might have to buy a few after you start selling. I have a couple computers with the dallas chip in them. They aren't dead yet, but they will eventually.

I'll have to put in some orders for extra components before I run out of the 10 I have left, some of them are spectacularly slow to ship. I'll also be unavailable from august to late september due to work at sea so it might have to wait a while before I can sell/ship them.

Found a good supply for packaging for the ALT12887, which should allow me to safely send them over regular mail (~2cm thick), and modified the board design to shave another ~70mil (~1/16") in height (which I needed to fit in said packaging). 1st batch PCBs will have slightly trimmed pins to fit in the packaging, possible future 2nd batch PCBs will have the new design and no need for trimmed pins.

I'll start selling & shipping them as soon as I get back on shore, around the end of September. There's a minimum order of 256 cases of the packaging so hopefully there'll be plenty of demand. 😁

After 3 weeks of leaving the system off and turning it on again, the RTC time has held with no time drift evident. CMOS settings also held.

Maeslin wrote:

Found a good supply for packaging for the ALT12887, which should allow me to safely send them over regular mail (~2cm thick), and modified the board design to shave another ~70mil (~1/16") in height (which I needed to fit in said packaging). 1st batch PCBs will have slightly trimmed pins to fit in the packaging, possible future 2nd batch PCBs will have the new design and no need for trimmed pins.

I'll start selling & shipping them as soon as I get back on shore, around the end of September. There's a minimum order of 256 cases of the packaging so hopefully there'll be plenty of demand. 😁

Oh there will be... just tell us when you're up and selling!

feipoa wrote:

After 3 weeks of leaving the system off and turning it on again, the RTC time has held with no time drift evident. CMOS settings also held.

Mind PMing a pic of the chip on the module? Can't remember which version of the 12887 ('genuine' vs 'Alibaba') I sent you.

Either way, glad to hear it works as expected! 😁

Actually, 3 weeks with no evident time drift? That's better than the real thing! 😎

Maeslin wrote:

Another little update: […]
Show full quote

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.

Sounds like you sent the alibaba chip to me.

I send one original, one 'rebadged', I'm just not sure who got which. I'll see if I can get a pic of the 'rebadged' ones over the weekend if you want to confirm. Of course, if it works just fine, it doesn't matter.

Only difference is, if it works fine, it gives me a MUCH cheaper source for said chips. 😁

Turns out, seems both the ones I sent for betatesting were 'rebadged' chips, so the fact they work is good to hear.

Thanks to Tr3vor and feipoa for their willingness to act as labrats.

Finished testing on 2 more over a very long period. Less than 1 minute drift after 3 months.

Stuck batteries in 6 more, programmed them and will let them sit for the next 2 months while I'm working/freezing my ass off offshore around the North Pole.

If those pass QC upon my return I'll begin semi-official sales (basically, PM me if you want one) and procure shipping supplies and components for a larger batch of 50-60 for public sales.

New batch will be ~100-120mil lower in height due to board redesign and shipping supply requirements.

feipoa wrote:

How much do you think these can go for? After shipping and such, a brand new RTC from Maxim is around $22 USD.

Anyone experience with these? 3 dollar seems a good try to get a woking part.

http://www.ebay.com/itm/291090319166?ru=http% … 9166%26_rdc%3D1

JaNoZ wrote:

feipoa wrote:

How much do you think these can go for? After shipping and such, a brand new RTC from Maxim is around $22 USD.

Anyone experience with these? 3 dollar seems a good try to get a woking part.

http://www.ebay.com/itm/291090319166?ru=http% … 9166%26_rdc%3D1

Or one to test your X-acto knife and soldering skills.

The boards i have still have their dallas like chips still working condition.
But to solder a battery on shouldn't be too hard, but looks is another thing.
Also i would like to make sure the inside battery are disconnected instead of recharging it.
I don't want to get it explode in my 486 case.