Dimmer switch incompattable with non-incandescent light bulbs
I just tried for the third time to replace the dimming light in the dinette with a more efficient bulb. It flashed and dimmed to around the power of a candle. The other two tries were a compact fluorescent from a local hardware store and a different led bulb from DHGate. This time an led bulb in another room also quit.
So I think that this condominium that was fixed up to sell has at least one substandard dimmer switch, that blows out anything but an incandescent bulb. The fix is clearly to buy a new switch from a reliable store and try again. I have studied electromagnetic compatibility, but this caught me by surprise. It does not affect the radio, or noticeably the wireless network. From what I know about regulations, I guess that this switch was smuggled into the US.