Dallas RTC battery replacement

Benchmarq RTC clock replacement

In a Swedish post about my Victor 386MX PC, I wrote about replacing the battery in a dead Dallas RTC. So, I figured I would devote a post to this process, as it is common that these units run out of battery and they can be saved quite easy. You will need:

  • A Dremel tool.
  • A 3V CR2032 battery + socket and a couple of cables.
  • Basic soldering skills.

The process is quite straight forward. It also works on other similar RTC:s such as Benchmarq and Odin. When I do these mods, I always install a 24-pin socket on the motherboard, to make it easier to quickly swap RTC:s if needed.

First, use the Dremel to grind down the material of the RTC next to PIN 16 and 20 as seen in the image below.

When metal shows, you have unveiled the battery poles!

Now, solder a couple of cables between these poles and the battery socket. RED = positive in the image below.

Attach the battery and place the RTC in the socket.


The trickiest part of this process in my opinion is actually to fit the socket, as it requires quite extensive desoldering. It might be an idea to use a different, less flimsy kind of socket than I am using in this post.

Dallas RTC socket
24-pin socket.
Dallas RTC fix.
Cables attached to the battery poles. RED = positive!
Thank you IKEA for the battery!

As seen below, this modification also works on other RTC:s such as ODIN and Benchmarq.

Benchmarq RTC battery replacement

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