How to repair a Cuckoo Clock Pendulum that won't swing
First of all, you need to check to make sure there are no obstructions affecting the time train weight. If the downward movement of the chain or the weight is obstructed, the pedulum will not swing. If anything is obstructing the movement of the chain or the weight, it causes a reduction in the power needed for the pendulum to operate properly. In addition to obvious obstructions, a slowed or stopped pedulum can be caused by a warped wooden clock case. If the chain is rubbing against a wooden clock case chain hole, it will affect the movement of the chain which will cause the pedulum to slow down or stop swinging. If this happens, you can fix the problem by making the chain hole a little bigger. This can be done by drilling the hole a little larger which will allow the chain to move freely.
If the chain and weights are free of obstructions, it could be a problem with the way the time weight chain is or is not wrapped around the sprocket wheel. A cuckoo clock time train has a set of wheels which gear into each other. The weight is hooked onto a chain which enters a hole in the bottom of the cuckoo clock then loops around the sprocket wheel, then exits another hole. If the chain is not properly looped around the first wheel spocket, it will cause a problem. You can check to make sure the chain is properly looped around the first wheel sprocket by slowly pulling up the weight. If the chain is in the correct position, you will hear a clicking sound as you pull the weight up. If it is off the sprocket, the chain will be hard to pull, you won't hear a clicking sound and the weight will rapidly fall when you release the chain.
If the weight chain is off the wheel sprocket, you can fix it by removing the movement, looping the chain back onto the wheel sprocket then reinstalling the movement. Another method to repair the problem is to take the back cover off the clock, turn it upsdie down, grab both of the chains and while looking at the sprocket wheel, dangle the chain loop around the wheel then pull both ends of the chain. This will cause the chain to firmly wrap around the sprocket. Hold the chains firmly at the base of the clock case and turn the clock upright. Although a little more difficult, this method can be faster.
