Question about Sears Craftsman LiftMaster Chamberlain Garage Door Opener Wireless Keypad Model 976LM Security+

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Electrical problem with logic board or terminal block

I just replaced the gears on a 1/2 hp Craftsman garage door opener. When I plugged the electricity in, there was a spark and minimal smoke and then the unit is completely dead. The spark seemed to come from the terminal block or the logic board at the top, back section. I am pretty sure I got all the wiring back to it pre-gear change places. It is an old unit, but would anyone know how to tell if it is the logic board or something else? Thanks, Tom

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  • dickkit Feb 14, 2009

    Same problem, except unit was powered up but chain was not attached yet. Then when I tried to operate it from the wall push button I got the flash and smoke and everything went dead. Inspected motor, capacitor, terminal block, and logic board but did not see any burn marks.

  • Anonymous Mar 23, 2009

    Same problem. Replaced the worm and drive gears on a Craftsman unit, put all wiring back to where it was supposed to be, plugged in for test run and BLAM! A spark, circuit breaker tripped, and a little smoke. I am thinking something was too tight and the motor could not turn causing it to blow? If anyone has any advice on this one I'd greatly appreciate it.



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Do you see burn mark on board? Is so and unit is older than 15 years, buy new one.

Posted on Feb 12, 2009


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