[Shop-talk] garage door opener problmes

[Wayne]

David Scheidt wrote:
> We've got a Sears garage door opener that's gone tits up.  It starts
> to turn the motor, moves a little bit, then gives up, flashing the
> light socket.  The photo eyes have the lights lit they're supposed to,

I have a 1999 production Liftmaster / Chamberlain opener which is 
probably almost identical with yours.  It started doing similar stuff 
last spring.  I discovered parts and entire motors or "head units" are 
readily available on ebay.  I bought a gear kit for about $28 with the 
whole shaft and worm gear assy.

What turned out to be the real problem was the housing had a bunch of 
vegetation (from bird trying to build nests on top!) and dead bugs. 
When the thing fired up, the air movement kicked up this mess and it got 
into the optical sensor that detects jams, and tripped it.  You can 
probably pull the front end cap off it, without taking it off the 
ceiling, and vacuum out the crud to see if that helps.

I cleaned out all the crap, replaced and lubed the gears, reflowed 
solder on the circuit board, put it all back together and adjusted the 
chain (hint - grab your calipers and find a 1/2" OD deep-well socket and 
use as a feeler gauge for the chain tension.)

If you mess with the electronics, the circuit boards are coded by the 
color of the "learn button" (red, purple, etc)

   -Wayne