Bob, call this number 1-800-528-5236 and they will do their best to help you. It is the number for a technical service representative at the manufacturer. It will help if you have your model number handy and are near the opener when you call.

Bob,
I own a lift-master security+ GDO that was installed in my home by the previous owners in 1998. Like you, I'm having exactly the same problem. Unfortunately, the person I spoke with at the 1-800 number for lift-master was not very helpful. I'm curious as to whether the technical folks for your GDO were able to solve this problem.

Thanks,
Chuck

Update:
This problem turns out to be a defective remote. The gdo and the remotes use 'rolling' codes. If one of the remotes reverts to a "fixed code,' then this problem occurs. Purchase a new remote compatible with the gdo and program that first. Now try programming each of original remotes. Whichever one does not program is the defective remote.

Chuck

Chuck;
This is the first chance I got to look at the postings. I have not called the service reps yet. You indicated that you were having the same problem. You mentioned that the gdo and the remotes use 'rolling' codes. If one of the remotes reverts to a "fixed code,' then this problem occurs. Did your orginal problem allow you to program either remote first and it worked then the second one (no matter what order the Remote A 'or' B was programmed first or second) would not take the code, as in my case. Could you elaborate on this?
Bob
,

My problem was similar to others posted, except we have two GDOs (139.53681) for separate single doors, and when we moved in only one GDO would open by the remotes, the other would not open with any remote. Worse yet, the previous owners had that second unit locked and I found out why... when I unlocked the door at the corded unit I returned home later to discover the door was open! I think (at least I hope!) it was on the same code as a neighboring GDO...
Anyway, was able to use JayDee's method of quick press of the red button instead of the 6 second version indicated on the instructions (after fully resetting the unit to clear from access that other opener out there), and now I have both doors responding to their appropriate openers!
Thanks to JayDee and all of you for your posts... it took me a while to read through them all, and I took notes hoping one solution would work, and it did! -Raf5043

Many apologies for the delay in sending this message. Have been out of town and only gotten back now.

Bob -- My problem was I could program the first remote "A" and it programmed. However, remote "B" would not program. If I cleared all codes on the gdo and programmed remote "B" first, it programmed, but remote "A" would not program. No matter what remote I programmed first, "A" or "B" it would program, but the second remote would never program.

The problem according to the technician was the 'rolling codes.' If the gdo is using 'rolling codes' and one of the remotes becomes defective and uses 'fixed coding' it will not program. His solution was to purchase new remotes and I am happy to report that his solution was correct. I purchased two new remotes. Both of these new remotes programmed. Of my two original remotes, one of them programmed, the other did not. The one that did not was the defective remote; i.e., the one that was using 'fixed coding.'

I hope this helps.

Chuck