The motor runs but the chain does not move, we just had it worked on 1 month ago and now this, please help

Whenever I have a service call that the customers are claiming they hear the motor but don't see the chain moving 9 times out of 10 it will be a stripped gear ! if this is the case call a professional to replace it , the cost should be around $100 to replace , if that's not the case look for a jammed carriage or trolley , this is the part that has the swing arm connected to it that is attached to the door and the trolley , Sometimes a machines adjustment can override it's travel limit simply by a loosening chain and travel beyond it,s original setting on the up travel only (never when the door comes down) When the door is going up and has added a few more inches of travel there usually is a stop bolt that is in place before the light cover of the machine , this bolt is there to protect the plastic light cover but I never install them because customers don't normally do maintenance on their garage door openers and tighten chains and adjust travel limits ,,,They call me ! if you do have a jammed carriage or trolley this bolt must be removed but since it is under pressure you must loosen the chain before doing so to take the pressure off , After you have loosened the chain you will need to unscrew the nut on the stop bolt which is a 1/2 inch standard socket,,,after the nut is removed you can whack out the bolt and the carriage will now be free from the jam , after tightening up the chain again remember to check the travel limit that got you jammed in the first place and back off a few inches in it,s setting ! Good luck and if I was any help to you please leave me a nice review , Thank you Glenn

IF THE MOTOR IS JAMMED (JUST HUMS) LOOSEN THE CHAIN AND ADJUST THE LIMITS AND TIGHTEN CHAIN.

IF THE MOTOR ACTUALLY RUNS AND THE CHAIN DOES NOT MOVE THE DRIVE GEARS NEED TO BE REPLACED. THEY SELL A KIT THAT INCLUDES THE BUSHINGS AND SHAFT. DO NOT BUY THE SMALLER KIT AND DO NOT REPLACE ONLY ONE GEAR (THE OLDER WORN GEAR WILL CHEW UP THE NEW GEAR) THIS MAY BE WHAT YOU HAD DONE - IF SO CALL THE SERVICE GUY THAT DID THE POOR REPAIR AND HE SHOULD REPLACE BOTH GEARS UNDER HIS SERVICE WARRANTY. ANYONE WORKING ON THESE SHOULD KNOW BETTER.

GOOD LUCK.

STEVE