On Saturday, August 17, 2013 6:24:48 PM UTC-7, Kashif Haider wrote:
The manufacturer, Chamberlain, is sketchy, but 5 blinks seems to indicate
a problem with the RPM sensing. Here are some error codes that may
apply to your model:
1 blink: Protector open, misaligned, or obstruction lasts more than 4 seconds
2 blinks: Protector shorted or connected backwards for more then 4 seconds
3 blinks: Command input shorted to ground for more than 4 seconds.
4 blinks: Protector intermittent
5 blinks: No RPM in the first second
6 blinks: RPM pulses detected after the motor was turned off
(perhaps forcing up travel)
Before working on the opener, unplug its AC power cord or
disconnect its circuit breaker in the breaker box because there's
plenty of exposed high voltage inside the opener. Stand on a wooden
or fiberglass ladder, never anything metal.
All openers made in the past 20 years or so have a sensor that measures
motor rotation (and therefore RPM, direction, and the force of any
obstruction), and Chamberlains use an optical type consisting of a
shutter/chopper wheel at the end of the motor shaft that rotates and a
small stationary circuit board housing an LED and optical sensor. They
may look something like this:
Because the sensor is optical, dust could affect it, so try blowing on it
through a straw or squirt canned air. If that doesn't work, try spraying
with isopropyl alcohol or CRC brand Electronic Parts Cleaner (hardware
stores, auto parts stores, and electronic supplies sell it). Be sure any spray
you use is 100% safe for all plastics by spraying some on styrofoam and
verifying that it doesn't affect it at all because some solvents will make
the LED and sensor frost up, rendering them useless.
While you're looking at the LED & sensor assembly, see if it's come loose
(cracked plastic, mounting screw worked out -- motor vibration is awful
for those things), and reseat its cable several times, both at the assembly
and at the other end that plugs into the larger circuit board. It also wouldn't
hurt to look at the solder joints of the assembly and where its cable attaches
at the big circuit board, again because of motor vibration. Cracks in
solder are oftne invisible without a bright light and magnifying glass.
About the only other things that will prevent motor movement are a
bad motor capacitor (about 1" - 2" diameter and 2" - 5" long, but a
bad capacitor will usually still make the motor buzz briefly) and a
bad motor relay. The big circuit board usually has 3 relays, 2 for
the motor (one for up, the other for down), one for the overhead lamps.
They're typically plastic cubes and are standard parts available from
electronic or electrical supplies (Mouser, Jameco, Digi-Key, Allied).
You need an exact fit, again because of motor vibration.
Protector connected backwards for more than 4 seconds?
How would it be connected backwards for less than 4 seconds? Perhaps during
installation if the installer noticed the error immediately, but in that
case the power probably wouldn't have even been on.
It seems strange to have a time associated with a reversed connection.
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