MY CLOCK RUNS A WHILE AND STOPS:  A clock should be in beat.  If the clock ticks are uneven the clock is out of beat.  Leveling the clock should restore correct beat.  A clock that is leaning forwards or backwards may have the pendulum rubbing against the case back, a weight, or some other component.  Modern tall case (Grandfather) and wall clocks usually have an automatic beat adjusting mechanism.  To use this feature, gently swing the pendulum all the way to one side of the case and release.  As the pendulum swing diminishes in arc, the beat adjuster sets the beat.  These autobeat mechanisms can wear, some are plastic and crack or shrink over the years.  Replacement or professional repair is required in these cases.

I JUST MOVED THE CLOCK, NOW THE CHIMES ARE SLOW OR STOP:  This is a common problem when three weight clocks are moved.  In most cases, you will find that one weight is heavier than the others.  The heaviest weight almost always is to be hung on the right hand side of the clock.  Clocks with large pendulums may have two heavy weights.  With these clocks the heavy weights are mounted on the right and center chains or cables.  Many manufacturers stamp L, C, and R on the weight bottoms for left, center, and right to help you install the weights in the correct location.

MY CLOCK KEEPS STOPPING AT THE SAME TIME:  Look very closely at the hands.  They bend very easily and can touch other hands, dial decorations, or the door glass.  Gently straighten the bent hand or call your friendly local clock expert.

MY CLOCK DOESN'T RUN AT ALL:  Don't overlook the obvious.  Is it wound?  30 day and 400 day(anniversary) clocks are wound infrequently enough that it's easy to overlook winding.  Electrical clocks may have been plugged into a switched outlet or a defective outlet.  The cord or plug may be damaged.  Quartz clocks may need new batteries.  You would be surprised how many times people have tried a different battery that was just as dead as the one in the clock.  Use good batteries, inexpensive zinc batteries tend to leak and have short lives.

MY CLOCK IS OVERWOUND:  No, I'm sorry, but it isn't.  When a spring wound clock is fully wound, the spring surfaces are pressed together tightly.  If the spring lubricant is old and sticky, it can prevent the spring from unwinding, so the clock has no power.  If the lubricant is this tacky, the clock is long past due for a complete disassembly, cleaning, and movement overhaul.

MY CLOCK RUNS FAST OR SLOW:  Mechanical clocks provide some means for adjusting the speed.  Pendulums typically have a nut below the pendulum bob.  Tightening this nut raises the bob and makes the clock run faster.  Loosening the nut makes the clock run slower.  You may need to gently press down on the bob to ensure it lowers, quite often the nut loosens and the bob remains stuck in place.  I recommend only turning the nut one full turn at most and waiting a day or two to see if addditional correction is needed.  Many mantle clocks have a small adjusting square near the 12 or below the hand shaft.  The winding key should be double ended, with a small square on the longer skinny end.  This is used to turn the adjuster.  Usually clockwise makes the clock faster, counterclockwise makes the clock slower.  Some clocks have an F and S with arrows to make this clear.  As with other adjustments, a single full turn at most and waiting a day to two to judge the effect is recommended.