My kitchen timer fell on the ground and it doesn’t make a sound. So I have to take apart the kitchen timer to see what happened inside.
Check Kitchen Timer
Before taking the timer apart, I have to examine if there are any additional problems with this timer. All the buttons work fine. It seems only the buzzer is malfunctioning. I guess a solder joint may have loosened because of the impact.
Take Apart the Kitchen Timer
It’s a little bit annoying because there are many screws on the back. However, it is very easy to take it apart.
Now I can see the loose solder joint is hanging over the buzzer. So my guess was correct. Regarding the buzzer, this buzzer is called a piezoelectric disk buzzer. It is driven by voltage. We can see the buzzer consists of a layer of piezoelectric material sandwiched between two layers of metal. When voltage is applied to the metal, the piezoelectric material will vibrate, causing the buzzer to ring.
Since two metal disks cover the top and bottom of the buzzer, it is very easy to make a new solder joint. All I have to do is use the iron to solder the joint in a different location.
You can see the new joint located on the left side of the buzzer. It works perfectly. Before assembling the timer, don’t forget to put the black rubber band in the right position. Otherwise your timer may not be water/oil proof.
If you don’t know how to solder, please reference the following video.