Fixing the bathroom scale

The bathroom scale stopped working.
Replacing the batteries didn't make a difference.
Thought about just buying another one (not so expensive).
Decided to take it apart, just to see if it's fixable.

Scale is on the bottom left of the picture.
Already took the plastic cover off.
It has a glass platform with four sensors at the four feet.
There were about 8 small screws to remove the bottom plastic cover, with some small plastic tabs to pry away to remove the rear cover.

Found the root cause.
The black wire connected to one of the battery connections had corroded and when touched, came apart (had lost continuity).

There's 3 AAA 1.5V batteries.
The negative connection on the right side of the pictures is the lost connection.

Cut a short piece of black wire from some extra wire to extend the length of the wire for the scale.
Without the extension, there wasn't enough material to solder onto the connection.

 

Used this wire stripper to strip the insulation off of the short extension wire.

Need to strip the insulation off the wire in the scale.
It's a very thin gauge wire.  Too thin for the wire stripper for the extension.

Used this automatic wire stripper in the smallest gauge hole (26).

Joined the short extension wire to the scale wire using a self soldering & sealing connector.
Heat is used to melt the built-in solder, the red sealing rings and to heat shrink, all at once.

Then, using a soldering gun and some soldering wire, the extension wire was soldered onto the battery connection.

The connector was placed back in the scale and battery installed.

Lights came on.

Putting the rear cover back on.

Done.

We'll see how long it keeps working.