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I have a small dehumidifier that I have taken apart because it was not working at all. It operates with a Peltier plate that cools the air being sucked in, to create condensation. Therefor dehumidifying the air going through the system. It stopped working altogether, and would not turn on at all. When I took it apart and disconnected the Peltier plate from the circuit board, everything began to function. When I would plug it back in to the circuit board, nothing worked. I bought a new Peltier plate and installed it, thinking that it was a faulty component. Of course, when I attached the new plate, nothing worked again. I noticed with a multimeter that when the plate is connected to the circuit board, the voltage drops for the entire board from 12V to around 1V or so. The solder joints look fine, and there is no visible damage to the board that I can detect. I have tried a lot of troubleshooting, and nothing seems to turn up any clues, besides when I unplug the plate from the board, everything else works again. What could be causing this issue? It began after I turned the dehumidifier off to empty the water catch, and then when I reinserted the container, nothing worked. All the components seem to work fine, including the Peltier plate which I have tested for continuity, and of course replaced with a new one. So basically with the plate attached, it seems to disrupt the entire circuit board, and with it disconnected, the board seems to operate properly for all other components which include a fan, an LED light, and a kill switch for when the water catch becomes full. I'm getting correct voltage to the connection on the board for the plate with it disconnected, but somehow when I reconnect it, the voltage for the entire circuit goes to barely over 1v rendering it inoperable. I'd love some input from anyone with ideas on what I'm experiencing, and if it is worth trying to fix. Thanks in advance!

If it runs from an AC source (converted to DC), check if the regulation capacitor (or any electrolytic capacitor) is with a flat top or with a half-sphere like top. In the latter case, the capacitor has dried out and does not work as a capacitor anymore. Try to change it for another electrolytic capacitor with the same or better voltage and capacitance ratings.

I thought the same thing at one point, but I didn't notice any bulging or anything on the capacitor. I think I'll change it anyways per your suggestion, and see what happens. Thank you.