My toddler son has a habit of throwing his toys, and his favourite is the Lego Duplo 10508 Train. After a few throws, the sound from the train became like a blown speaker. Last week, the sound from the train stopped altogether.
It’s not as nice to play with without the sound effects, so as any father might do, I took the train apart to see if it can be fixed. I found this Youtube video that shows how to take it apart: Lego Duplo Train Engine Repair Video
Be warned that it was quite difficult to remove the the tabs from the slots, and I strained the plastic a little on the back of the train trying to get the rear tabs out. You have to pull the black plastic outward while pushing the red plastic inward to get the tabs released. The slot is on the red plastic.
Once I had the cover off, I found the speaker was in this condition:
As you can see in the photo of the back of the speaker above, the terminals of the speaker has been sheared off. No wonder there wasn’t any sound!
Here are the specifications of the speaker in the Lego Duplo 10508 Deluxe Train Set:
I tried looking for an exact replacement, but failed to find a speaker with a diameter of 21mm and coil impedance of 32Ω. I ended up with a speaker with a diameter of 19.9mm and coil impedance of 8Ω from RS-Online: Kingstate 8Ω 0.08W Miniature Speaker 19.9mm Dia. 19.9 x 4mm (LxWxD)
The important thing is that the diameter must be 21mm or less to fit in the space for the speaker in the plastic. It must be able to sit flush against the red plastic otherwise the red plastic casing will not fit over the speaker. I stacked 4 pieces of double sided tape to make up for the missing 3mm height and stuck the speaker to the plastic tab.
Now my son can go back to enjoying his favourite toy, and hopefully he will stop throwing things around soon!