This is the Model 308 unit. Turn it over.

There are 3 screws that have to be loosened.

Remove the cover and set it off to the side.

The shiny round disc in the black holder is the battery.

Push the release tab (at the point of the screwdriver) all the way and the battery will pop up.
You have to push flat on the top edge of the tab.

Don't push down, push horizontally.
If you push too low the screwdriver will
prevent the battery from popping up.

You can use your finger nail if you do it right.

The battery's edge will jump up visibly when the catch is released.
Lift the battery out.

Next: Leave the unit unplugged with the battery out for at least 24 hours!

Now put in a fresh battery, put on the back cover and plug it back into the wall. This "re-boots" the computer chip and corrects a blank display or other problems. The display should show all 8888s for a second or two, then go to the default - 12:00:00 and start counting seconds.

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