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glitch
July 27th, 2017, 05:13 PM
I started repairing an old 486-based industrial system today, which uses a 486 SBC in a passive ISA backplane. Most (but not all!) consumer hardware uses a RTC with a little CMOS RAM and an external battery and crystal, but potted modules are common on industrial/embedded hardware. Unfortunately this one uses a DS1387, for which there is no modern replacement. Several other people have repaired the DS1387 and posted writeups on the process. Here's my rebuild:

http://www.glitchwrks.com/2017/07/27/ds1387-rebuild

I used a CR1225 and holder due to space restrictions, here's the final result:

http://i.imgur.com/gyj2PgI.jpg (http://imgur.com/gyj2PgI)

TravisHuckins
July 27th, 2017, 05:45 PM
I'd be interested in buying a modded DS12887 with a CR2032 battery holder if anyone is making any, even though they are still produced.

glitch
July 27th, 2017, 06:02 PM
I'd be interested in buying a modded DS12887 with a CR2032 battery holder if anyone is making any, even though they are still produced.

There's this guy:

https://oshpark.com/shared_projects/NwcVatSK

It uses a DS12885/BQ3285 in SOIC (surface mount) with external battery and crystal. The DS12885 is the exact same IC used in the DS12887 module, but intended for external battery and crystal. This is the way to go, unless you have DS12887s and want to modify yourself.

That design appears to be open, if people are interested in assembled units I'd be happy to run some, though I might rework it to use Batten and Allen flat pins. The board is small/cheap enough it's probably not worth doing a big run -- it's $3.60 for three boards from OSH Park.

EDIT

Actually, what might be even better and cheaper is a regular DIP DS12885 and battery/crystal carrier board, just bend the battery and crystal pins up just like they do with the potted module.

lowen
July 28th, 2017, 03:47 AM
I started repairing an old 486-based industrial system today, which uses a 486 SBC in a passive ISA backplane. Most (but not all!) consumer hardware uses a RTC with a little CMOS RAM and an external battery and crystal, but potted modules are common on industrial/embedded hardware. Unfortunately this one uses a DS1387, for which there is no modern replacement. Several other people have repaired the DS1387 and posted writeups on the process. Here's my rebuild:

http://www.glitchwrks.com/2017/07/27/ds1387-rebuild



Very nicely done. I have a number of these industrial boards here as well, and this is useful.

glitch
July 28th, 2017, 10:06 AM
Very nicely done. I have a number of these industrial boards here as well, and this is useful.

Do you have the exact Multitech board that I was working on? I haven't seen a lot of their hardware "in the wild," would be interested in knowing what they were installed in. Mine was in a gutted RAS/terminal/application server device that someone had been using for other purposes (no comms board, hard disk had a plain DOS install).

lowen
July 28th, 2017, 10:36 AM
Do you have the exact Multitech board that I was working on?

No, most of the ones I have are Advantech, but similar design. I haven't seen one with a DS1387 yet; most are DS1287 or even one DS12B887.


I haven't seen a lot of their hardware "in the wild," would be interested in knowing what they were installed in. Mine was in a gutted RAS/terminal/application server device that someone had been using for other purposes (no comms board, hard disk had a plain DOS install).

Multitech made a lot of industrial modems, as I recall. I have seen these industrial SBCs of several brands, again mostly Advantech, in things as varied as a cellular network impairment simulation test set, controllers for Motorola/Synchronous supertrunk fiber optic converters, Cisco Metro 1500 DWDM fiber mux/demux boxes, and other places where something beefier than the typical 68HC11 or Z180 microcontroller board would be used (those being of essentially the same vintage as a 486 SBC). The Advantech 6144 and 6145 series are very similar boards, but half-length and only one or two SIMM sockets.