I have a B & D controll-a-door 4 (CAD-4) opener for a tilt garage door. The model no. is 062200 and the unit was installed about 20 years ago. About a week ago, the motor started running constantly, even when the door was not in use. Needless to say, the opener does not function - just the motor running non-stop. I've had to disconnect the power supply because of the noise.
I've been told it might be a worn drive gear but when a repairman visited, he said the problem was the circuit board (although he didn't actually look at it). He said replacing the circuit board was not an option because the (long) antenna is 28 MHz which is no longer made. Only replacement boards with (short) 433 MHz antennas are available and they are not compatible with my unit. He said due to its age, the whole unit would have to be replaced with a brand new opener. Does this sound plausible? I'm a keen re-cycler and would rather repair than replace so I'd appreciate any advice.