Door goes up, Won't go down.

check safety obstruction lights mounted close to bottom of door.
The most likely reason is that your lower travel limit needs adjusting. Your door may have settled or shifted due to age and weather changes and now contacts the floor before the lower limit switch is triggered. The opener sees that as the door not being able to close completely and, since that could be caused by something or someone trapped under the door, it reversed the door back to the open position as a safety precaution.

If the door only does this with the remote and you need to hold the wall switch button continuously to bring the door down then there could be a problem with the safety sensors near the bottom of the garage door itself. Again, the opener would see a problem there as a potential safety concern and re-open the door. Typically, however, a safety sensor issue will cause the remotes not to work at all and will reverse the door long before it reaches the floor. And any problem with the safety sensors should also trigger flashing of the overhead light.

Your owner's manual and the links below have more information that should help locate and resolve the issue.

Your not clear what is going on but my door would not close because the sensor near the bottom of the door as not lined up with the other side. they both have to be in line with each other and also if there is dirt even a leaf over the sensor on either side it won't work either. Is your sensor wire on the over head box out in the open where it should be? If its not opener problem I don't know as you are not clear.

Sensor must show steady light to close circuit and let opener work. If aligned, then there is a loose or broken wire. Try reaiming first to get steady light. Then check all wires . Another way to test and prove that is the issue is if u hold down the wired button at ur back door and the opener closes, then it is sensor issue. Good luck.

disconnect motor, check the door is operating smooth and correct. check springs. check downward pressure setting

If the overhead light flashes 10 times and the door reverses to the open position it is a door sensor problem. Make sure the lights on one of the sensors is not blinking ever so slightly or the light is dimmer than the opposite one. Check to make sure they are connected properly. The solid white wires go to terminal #2 and the wires with the black stripe go to terminal #3.

HOLDING DOWN THE WALL BUTTON OVERRIDES THE SAFETY EYES.
WHEN HOLDING IT DOWN MAKES THE DOOR CLOSE PROPERLY THE PROBLEM IS IN THE SAFETY EYES.

ARE BOTH LEDS ON? - CHECK FOR A LOOSE OR BROKEN WIRE.
ARE THE EYES WIRED CORRECTLY?
ARE THEY AIMED AT EACH OTHER?

I WOULD RECOMMEND GETTING A SURGE PROTECTOR FOR THE NEXT TIME.

If when the door reverses the main light flashes 10 times it is a door sensor problem. Make sure the small light on each one is lit and not flickering. Tweak them a bit. If you can't get both lights to come on you have either bad wiring to the sensor or the sensors are bad.

It sounds like a logic board problem to me. I would remove the board and look for bad connections especially around that small transformer.

Unplug unit at power source and check and tighten all connections in the control box. And try this link.

http://www.garagedooropeners.us/technical_information.html

Mike

Problem solved, sort of-
My unit has self diagnostic capabilities: next to the remote sync red button, is a yellow light the indicates diagnostic readings by blinking. In my case the light was flashing 5 times after the door failed to close. This meant RPM sensor failure. I rechecked the sensor and "flywheel" cap and found that it was not completely secured. With the "flywheel" in the proper position, providing readings for the RPM sensor, the door completely closed.
But my yellow diagnostic light is still flashing 5 times. My door is operating correctly, but the diagnostic feedback is still not completely happy with my RPM sensor. So I will keep and eye on it.