Dallas Replacement

Overview

Replacement for CMOS RAM. Replaces the potted RTC device. See compatibility list below.

Problem with the potted RTC is that the battery will run flat and there may be no easy or clean way to fix the problem. Some systems will not boot with a flat battery.
Dallas Replacement essentially removes the potting and makes it easy to change the battery, ensuring that your hardware will hopefully stay functional for much, much longer with a simple battery change once in a decade.

Also included is a button for clearing the CMOS RAM.

Size-wise the Dallas Replacement is about 0.5mm wider and about 3mm taller when including the battery holder.

Compatibility list

  • DS1285
  • DS1287
  • DS1287A
  • DS12887
  • M48T86
  • HT12888A (CMOS clear jumper, if present, won’t work; clear with on-board button)

May be compatible with other parts as well. Please send me a message and I can see if I can find out if this would be compatible with your specific RTC.Likely compatibility, but cannot be guaranteed

  • DS12C887

Ordering information

To further increase the chances of successful replacement; when purchasing, please add as a message to the seller information on what your current RTC part number is. Pins will be trimmed accordingly.
If you wish all pins left untrimmed, let me know. In such case, pins will match the DS1287 datasheet with the exception of pin 16 which instead of NC will be GND. Even pins that are internally NC will be left untrimmed.

If no extra details are given, I will send a version where pins are cut as they are cut in a DS1287. This should work for majority of cases.

Installation tips

I strongly recommend that you don’t directly solder the part onto the motherboard, if possible. I recommend that you solder a 24 pin IC socket onto the motherboard, and plug the Dallas Replacement into that socket. This way, if anything goes wrong or doesn’t work, you don’t have to do any additional soldering.

What’s included

Includes fully assembled Dallas Replacement board and a CR1220 battery.
Pictured original Dallas RTC component is for reference only and not included.

Purchase

I sell on Tindie

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