I have an old SC503 X-10 Maxi Controller. Its main use is for me to press "all off" when going to bed at night. Recently, it stopped sending the all-off command. However, I can still send commands to individual modules. For example, pressing "6", "7", "off" works fine, but pressing "all off" does nothing. (The bedroom lights happen to be D6 & D7). That makes it sound like the problem is the switch itself, but the indicator LED still operates normally so the switch must still work.
Any ideas? Pat