Reviving long-dead Dallas DS12887 RTC ICs

[rdmark]

If you have looked inside many a 90s PC, you will probably have spotted one of a range of Dallas manufactured RTC chips. These are integrated circuits that handle the real time clock, as well as containing an internal lithium battery to drive the CMOS circuitry. When these ICs run out of juice, it can be challenging to replace it.

Enter battery modifications for these Dallas chips. I made this video to document my exploration of one particular mod, to understand how it works through the data sheet, and how to install it properly.

This is the particular mod board that I used. You can definitely do it without the board, simply gluing a battery holder onto the package, but it's neater this way I think!

GW-12887-1 Repair Board for DS12887 RTCs by Glitch Works, LLC on Tindie

GW-12887-1 Maintainable Repair Board for DS12887 RTC Module -- NEW

www.tindie.com

 

[lobust]

Going to watch this one later, thanks for posting.

Not a PC, but I have and still use a CNC machine that was built in 1992 that has either three or four of these on it's memory board.

 

[rdmark]

There was some very informative discussion in the comment section of my first video, and I was made aware that the DS12887 already has an internal oscillator (which in hindsight I should have noticed) so hooking up another one in serial breaks the circuit design. I made a follow-up video to validate the theory and correct the mod.

 

[rdmark]

I shot yet another episode of this unlikely Dallas clock chip series. This time I mod it properly! Promise!