I have one technique. I opened the receiving end and desoldered the sensor diode. When stimulated by the transmitter, this diode should close or open it's own circuit, depending on the design. That will cause the receiver's logic to behave however it's supposed to. So, feel free to leave it an open circuit, or to close it by soldering in a wire. Reassemble and reinstall.

In my case, the experiment only indicated that the damage to my opener lay within the opener itself. So, doing this didn't solve my problem. I just thought I'd pass along what I came up with in the process of diagnosing my opener.

I also had a Chamberlain GDO, model #41A5389-1 with a broken IR sensor.

Adam and the guy who said to just point the sensors (might have to replace them) at each other are both right.

The circuit is not a simple NO/NC (normally open/normally closed) as was the case in most older GDO's. Therefore a person is unable to easily bypass the copyrighted "Protection System" by opening or closing any circuit.

In fact, there is a specific trouble code that is given when the wires to the IR are shorted or open.

Internally on the PC board, this "Protection System" is part of the processor that also controls the motor. The safety features must be present for the motor to operate, else you are returned with an LED error code:

# flashes - Problem
1-The Protector System wire open or totally misaligned
2-The Protector System wire shorted or black/white wire reversal
3-Door Control or Multi-Function control Panel wire shorted
4-IR sensor slightly misaligned (dim or flashing sensor LED)
5-Motor overheated/Possible RPM sensor failure -- unplug to reset
6-Motor circuit failure -- replace RX/LX board
Rapid-Chamberlain transmitter with the correct format code being received
(opener not necessarily programmed to respond)