View Full Version : 12887 hack horror story (with a happy ending)

April 8th, 2014, 09:50 PM
I shut down and restarted my Pentium-100 Shuttle HOT-553 board last night and discovered that the DS12887A was dead. So I chewed up the top of the RTC chip from just past the clock symbol to the far end of the chip, and extracted the battery (it's a BR1225 in there, BTW), and got ready to add a CR2032. [The crystal is at the clock symbol end so don't mess with it.] I thought that I should make sure everything was OK before I soldered on the coin cell holder. So I hooked up the power, inserted the video card, and switched it on. The board wouldn't fire up.

I decided to try reseating the BIOS ROM, which is right next to the RTC chip (maybe I bumped it). To my horror, I saw that two of the "pin clips" from the cheap BIOS ROM socket came out of the socket with the ROM. Oh, no! It was kind of odd because they were pins 14 and 15 (bottom corners of the chip). Clearly that socket was done for.

Well, the ROM was already out, and I was going to be doing some soldering anyway... I cut the damaged socket off the board, in sections, and pulled all the pins and sucked the solder out of the holes. Then I soldered the BIOS ROM in without a socket (I've had the board for almost 20 years so I don't think I'll be upgrading the BIOS anytime soon). I rechecked with the video card, and the board fired up. So I soldered the coin cell holder in place, and secured it to the remains of the DS12887A with 5 minute epoxy, and it looks like everything is back together and working again.

April 9th, 2014, 07:23 AM
If you're gonna use a socket, be sure to make it a machine-pin one. They rarely fail.