We just installed a new Chamberlain Power Drive Security + garage door opener, Model 248735S 3/4 HP to replace a Craftsman Model 139.53674SRT2. The outdoor Craftsman Security + Keyless Entry, Model 139.53684 instructions from the old unit say that it is compatible with any Security + garage door opener receiver. However, we have not been able to get the new unit to learn the code. The lights on the opener are supposed to blink when the code has been learned, but don't, and the keyless entry won't operate the door. We tried using the learn button on the new unit, as well as using the multi-function door control, to no avail. Our old Craftsman unit only had a basic wall control, not multi-function. Don't know if that makes any difference. We also put a fresh battery in the keyless entry. Any ideas on how we can get the new opener to operate with the old keyless entry keypad?