I have just got around to a serious look at this, originally my assumption was that it was the remote failing to work properly..
It is a large portable electric fan, three speed, timer to go off, variable direction, with a random function. Control is via IR remote or buttons on the fan. As the control IC it uses a SC8206 18 pin, with green LED to indicate function and a tiny piezo buzzer.
The original problem was it sometimes failed to respond to the remote, which became worse over time. Then the buttons on the unit itself became iffy.
It uses a capacitive type power supply, with an X rated cap from the mains, followed by diodes and resistors, a smoothing cap, then a zenor. Which is supposed to provide 5v to the control system. With nothing running, no LED's lit, it does provide the 5v, but that falls to around
3v when anything is powered, any current is drawn. I can turn it off via a button on the unit, the remote will then work to turn it back on, but no further response to remote - obviously because the rail voltage has fallen to 3v.
Prace your bets on the likely failure mode? X rated cap, diode rectifier, smoothing cap maybe? To be fair, the smoothing cap looks fine and is rated 16v.
I'll get back to it with some serious diagnostics in a day or two.