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

1 Answer

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

Posted by on

  • 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.


1 Answer

  • Level 2:

    An expert who has achieved level 2 by getting 100 points


    An expert that gotĀ 5 achievements.


    An expert who has answered 200 questions.


    An expert whose answer gotĀ voted for 20 times.

  • Expert
  • 244 Answers

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

Posted on Feb 12, 2009

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

My light won't go off on my craftsman 1/2 hp garage door opener.

This is usually caused by electrical storms. The light is controlled by a relay on the logic board and the contacts must get welded.

Sep 23, 2010 | Sears Craftsman LiftMaster Chamberlain...

1 Answer

How can I test the Receiver Logic Board for Craftsman 1/2 HP Garage Door Opener Mod.139.53962SRT1

The only way a homeowner can test a logic board is with a good remote that is programmed to that logic board.

Jun 20, 2010 | Sears Craftsman LiftMaster Chamberlain...

2 Answers

Have a Craftsman 1/2 HP auto gargae doors. Lost power during a snow storm. Once power was reconnected only thing that did not work was garage doors. Is there a reset button somwhere....can't see one.

There isn't a reset button. Check the house circuit breaker. You may have had a power surge and that can damage the logic board printed circuit. Check the logic board for missing or burnt traces especially around the small transformer.

Feb 14, 2010 | Sears Craftsman LiftMaster Chamberlain...

1 Answer

Craftman Garage Door Opener Quit Working.

It could be a bad logic board especially if you have had any electrical storms in the area. I would remove and check the logic board for burnt or missing traces on the printed circuit board.

Sep 14, 2009 | Sears Craftsman LiftMaster Chamberlain...

1 Answer

Power is on, lights come on but just hear a click

Odds are you have had an electrical storm and you need a new logic board.

Sep 01, 2009 | Sears Craftsman LiftMaster Chamberlain...

1 Answer

How do we reset our Craftsman 1/2 HP Part# 41A4315 - 7A garage door opener? When you press the button is goes down a little ways and then back up. The little green sensor lights will not come on either,...

If the lights in the door sensors do not light you have either a bad logic board or bad wiring to the sensors. Replacing the logic board is usually the cure.

Jun 05, 2009 | Sears Craftsman LiftMaster Chamberlain...

1 Answer

Sears 1/2hp thinks it is not all the way up and will not go down

It is really a common problem for lightning or electrical surges to take out the logic board. Big expense too.

May 29, 2009 | Sears Craftsman LiftMaster Chamberlain...

1 Answer

Electrical Problem with Sears opener

Hi there, i would suggest a break point test with a voltage test needle. Im sure that this electrical surge has torched your power supply board. this is the reason for the non operative state.

Feb 17, 2009 | Sears Craftsman LiftMaster Chamberlain...

Not finding what you are looking for?
Sears Craftsman LiftMaster Chamberlain Garage Door Opener Wireless Keypad Model 976LM Security+ Logo

207 people viewed this question

Ask a Question

Usually answered in minutes!

Top Sears Garage Doors Experts

Al Clark

Level 2 Expert

290 Answers

Cindy Wells

Level 3 Expert

4757 Answers

Pieter Vleeshouwers

Level 3 Expert

1417 Answers

Are you a Sears Garage Door Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides