So, I took apart a cheap electronic push-button sound effects toy with wires hither-scither in it, then put it back together, but it didn’t work. Ut oh, did I break it? Maybe, but I was able to mitigate the damage to effectively repair it, given the constraints of its cheapness.
The problem was that when I closed back up the case, I wasn’t careful about how I was rerouting the wires, so when I tightened down the screws, I squashed two wires: the power wire and the speaker wire. Just enough to totally destroy the original function of the toy. But, never fear, given the constraints of this being low-power and low frequency electronics, it was an easy fix. I looked at the squashed wires, and carefully bent them back to their original shapes. I could still feel there to be stiffness in the bent wire sections, so I had hope that there was enough wire held tight enough together to give me electrical continuity. Then, of course, I carefully routed the wires and carefully paid attention to their positioning when closing up the case, and this time I confirmed that I could screw down the wires without feeling like there was any additional resistance in the way. Batteries put back in, and what do you know, it worked.
What made the idea of replacing theese wires particularly challenging was that they were really thin wires and had tiny solder joints. Luckily, I was able to make the repair without needing to consider that complication.
Again, it is worth noting that higher poewr and higher frequency circuits are less forgiving, in these cases you are beter off just replacing the wires whole.