I have a 12+ yr old Craftsman GDO, and the receiver sensor is now refusing to work when it's below freezing. The green light is off when it's cold (as others have posted here), the GDO light flases 10 times when trying to close, I've re-aimed it, checked the wires, etc. I tried warming the whole sensor on a 40w light bulb for a few minutes, and it worked temporarily, so I'm pretty sure it's the sensor. Has anyone tried to repair one? I've found the sensor pair for about $35 locally, but I can't believe the couple of transistors, capacitors, and the photosensor could wear out, could they? My best guess is maybe a bad solder joint? I disassembled the sensor and everything looks normal.

Here's a tip I tried for checking the beam sensors: Most cell phone cameras and some digital cameras can 'see' infrared (to some degree), so you can use them to find out which black box is the transmitter, and if it's working. In a fairly dark garage, I was able to see a pinpoint of light, coming from the transmitter, on my cell phone screen at about 10-12 feet, probably would have worked better if it had been completely dark. At 1 ft, it was clear it was transmitting. It probably does nothing for aiming the beam, but at least you can see if it's working or not.

Any ideas?

Re-soldering many of the connections didn't help. When left in the freezer and reconnected while frozen, the green light still wouldn't come on until it warmed up (above freezing). I tried warming the top of the largest capacitor (carefully!!!), and the green light came on when it warmed up.

I replaced the 470uf (microfarad) capacitor, the sensor survived the freezer, and worked immediately when hooked up, still good and frozen! I left the 10uf one alone, though I should probably have replaced it too. The part should be available at any electronic-parts store, should be under $1 I would guess.

One warning: be sure to observe POLARITY of the capacitor BEFORE you remove it. The circuit board on my sensor had a + for each of the two capacitors, and the capacitors themselves are marked with a stripe of - - - on the negative side. Also, make sure to get a capacitor that fits, my replacement was just a bit taller, but still fit fine.

I can't guarantee this will fix your problem, but it worked for my situation, and it's worth a shot to save the $35-$45 they want for replacement sensors.

Hope this helps!