There is always the chance that the remote or receiver has quit but we don't know which. The older units had dip switches on both the remote and the logic board. This is a set of miniature switches that have 3 positions and must be set exactly the same for the unit to work. You will find them near the battery in the remote and near all those white wires on the opener.

I have a sears 139.53778 transmitter. It has to be early 90's. It has 3 buttons. 1 larger and 2 smaller. Also a red l.e.d. light. Everything worked fine but someone "locked out" the transmitter with the "lock" button on the wired unit from inside the garage. This wouldn't be an issue but that "someone" also locked the only other entrance to the garage from the inside. I don't want to break in so.....Is there any way or sequence of pushing the buttons on the transmitter to reset the opener with the transmitter buttons? P.S. I tripped the power breaker to the garage from the house but that didn't work!!
Thanks for any help!

There is no way to reset the transmitter. Sorry.