Garage Door Opener DIY

Troubleshooting your garage door opener.

We understand there are many types and makes of garage door opener. Our goal in this DIY session is to give an overview of common symptoms that occur and how they may be repaired without the help of a professional. Not all repairs with an opener are simple. Some will require some expertise, while some are super DIY type repairs that almost anybody could preform. We will cover the simple DIY stuff here.

We do ask, with a concern for your safety, that if you are in the least bit unsure of your ability to repair your issues please do attempt to just watch a you tube video and call yourself an expert. Though we appreciate your call, we would rather you call any insured and licensed company. We wouldn’t like to see you make a mistake that could be potentially life changing. Though many quick fixes work and are not dangerous, anything to do with heavy objects over your head, that have substantial spring tension can be dangerous even to a specialist.

Garage door opener gears

The gear we will use as an example are from the Chamberlain, Liftmaster, and Craftsman model chain drive operators. There are two ways this assembly fails. This repair requires the most expertise of all listed here. It requires knowledge of the inner workings of the operator and a good understanding of the limits and electronics in your operator. If you decide to tackle this repair, all we ask is that you please unplug the operator before tearing into it.

  1. The nylon gear inside the box strips out and fails.

    stripped nyon inner gear for opener
    Stripped nylon gear inside the opener
  2. The top bushing fails and begins to cut into shaft of gear assembly. This is evident from the chain beginning to sag and there being shavings on the top of the opener. Some sag and a seemingly loose chain is not always a sign your gear assembly is going bad. Sometimes it has just worn loose and needs adjusting. We suggest to look on the top of your opener for metal shavings/graphite. If there isn’t these signs of wear, just tighten your chain and off you go! Over-tightening will cause the chain to slap the rail when in motion just an FYI so you don’t worry. Just back it off a little and the slapping will stop.   

    garage opener gear failure
    shavings on top of opener
    garage opener gear failure
    sagging in the chain can (not always) mean your gear assembly is about to fail.
    garage opener gear failure
    Shavings fallen in and on top of nylon gear

    Rocket City Garage Service always replaces the entire assembly and cleans the inside of the operator to ensure that nothing foreign can cause damage to the new gear assembly. Plus we provide a multi point service inspection. We tighten, tune and lube up to 4 doors on site. All for one price.


     Garage door opener photo eyes

If your door goes up like normal but you have to hold the wall station button to get it to come down, it is generally the photo eyes. You may notice that without holding the button it will return to the open position and click numerous times or the light flashes or both. As you may have already learned, your remote will only open the door but will not allow it to close.

All openers manufactured after 1992 have what we call photo sensors aka eyes. They, by law, must be mounted on the track or wall beside the track at 6 inches from the floor pointing across the opening of the door. They tell the garage door opener if there are any obstacles in the way while closing. They can be a pain if not aligned and fastened well. It is very common in our line of work to find that the alignment or wiring for these components is amiss.  We find many times that the components show the correct light and as the door is coming down it gets to a point and reverses. This is indicative of either wiring failure, or loose track and or sensor harness is loose. You can troubleshoot this pretty easy. Here are a couple of video demonstrations. Again, your operator may be different in that it only has one sensor/eye with a light. They all pretty much do the same thing when obstructed.

Garage door opener adjustments

All garage door openers have limit adjustments and generally a force adjustment. The limit sets the travel of the door open and closed, while the force sets a tolerance of energy it needs to open and close the door. The force adjustment is a form of safety as well. When set correctly it will stop and reverse the door should it hit something the photo eyes don’t see. In modern residential machines the force setting doesn’t add power to the machine, rather, it allows a variable in the machines RPM sensor to be overlooked or more scrutinized depending on how you set it up. Over time the settings will need adjusting as the components and electronics in the opener become less accurate. Always refer to your manufacturers safety precautions for the proper adjustment of the force. We do find many times that when a machine has its force turned all the way up and still has trouble moving the door in any direction,even though by hand the door is balanced and is easy to lift and close, it is time to replace it altogether. Last but not least, if your door goes part way up and then just stops, or worse, falls back to the floor, please give Rocket city a call. This could be something simple or something to do with the door itself causing the operator to halt movement. Without a technician looking at it,  it is tough to diagnose.

Emergency release

All garage door openers are equipped from the factory with an emergency release feature. We have found on many service calls that it was released without the client knowing it and they wondered why the door wouldn’t open. Below is a demonstration of A Liftmaster, Chamberlain, or Craftsman emergency release.


Wall Stations, Remotes, Key pads.

Wall stations, unless they are the doorbell type single button, have a lock feature. Please note that if the lock is engaged the door will only work from the wall station and all remotes including wireless keypads will not work. Most Liftmaster, Chamberlain,or Craftsman wall stations blink when the lock is engaged, others like Genie or Overhead have a switch on the top of the wall station. If your remote that once worked for your door simply stops working, Definitely check out the battery. I know that sounds like a “duh” statement but we see it where the new battery wasn’t making a difference and upon opening the remote we find something keeping it from getting power.


Give Rocket city a call for a free estimate on repairing or replacing your operator.