My mom is obsessed with dehumidifiers. When one of the three in the house stopped working (it was old and in bad shape when we got it, so it was no surprise that it broke) I of course jumped on the opportunity to tear it up, even though my mom was upset. It was already partially apart when I got it, because my dad had been trying to fix it. I was most interested in the two PCBs inside.
One was the control board, attached near the top of the unit, that you could adjust the dehumidifier settings, such as the on/off time, desired humidity level, and fan speed. Another PCB buried deep within served to connect the rest of the mechanical parts of the unit to power. There’s some relays, a large cylindrical electrolytic cap, an even larger ‘boxy’ cap, and a transistor with a heat sink.