I repair some old automatic garage doors and there is some chip with mark MIC Y22760A that it seems to cause the problems. Problem is that I can't find the datasheet for the chip.
This is the right one:
Why do you refer to a commercial site without information to your chip.
Instead of posting a photo (100kBytes should be sufficient) of the chip on your pcb
that gives us informations like logos, marking, parts around
Probably a programmed MCU but the code would be specific to that product. The IC itself may be generic but the part number chosen by the unit manufacturer to indicate what code was inside it. The date code is 30 years old so I doubt you would find a drop-in replacement but if you can trace the schematic around it there is a chance you could find a pin-out compatible device and write your own program to drive it.