Not exactly double voltage, just two supplies in parallel for a short time that are both supplying approximately the same voltage. But their interaction (especially if switches were flipped in the box while the fan was running) could maybe produce a voltage spike that damaged the control board. I'm not really a fan expert but I assume there is a little board in there with a logic chip to receive commands and relays and such to control everything. If just one function didn't work, maybe an electronic technician could find a specific part (like a relay) to replace, but since multiple functions aren't working, I suspect too many things are fried to make it worth looking at. Maybe Contact the manufacturer and see if they have a replacement board.

Thanks toxcrusadr Contacting Hampton Bay was on my list of remedies. Didn't occur to me about there being a control board but it makes sense that it would have one. Appreciate the suggestion. Stick