My six year old Max E therm still works great but the "temperature up" button doesn't work. All the other buttons work fine and the heater also works well. They sell a replacement membrane which is $75 or the entire control board kit for $250. Not sure which way to go and would hate to start swapping parts for nothing. Any ideas? My gut says to buy the kit that way I'm not messing around with wafer thin membranes but wanted some thoughts first.