SFTC Equipment: Big Clock Instructions

Big Clock Overview:

Big Clock photo click to enlarge

The big clock costs approx. $4,000 to replace. The clock is large and heavy. It takes 1 strong person or 2 people to carry and it won't fit into most small cars. It's mostly used on large races. The big clock is easy to operate and fairly easy to synchronize with another clock. The big clock package includes the clock and a stand. The recharging cable is permanently connected to the clock. A storage/carrying box is sometimes used to provide additional cushioning while transporting. But the carrying box will only fit in a large car or a truck.

The clock has a keypad on one end which contains various controls for the clock.


The clock’s rechargeable battery should be charged for approx. 4-8 hours before use. The big clock must be handled carefully. The internal workings are very sensitive to bumps, humidity, and cold. The clock stand should be placed on a level and stable surface. With 2 people holding the clock, a 3rd person feeds a long bolt through the stand mount and clock base, placing a wing nut on the other end to secure the clock. The clamp on the stand that keeps the clock from rotating is broken, so don’t try to tighten it..

Starting the clock:

Flip the clock switch to ON.

To start the clock at the start of the race, flip the power switch to ON. Then push the CountUp button when the race begins.

However, for long races you may choose to save battery life and start the clock later in the race. To synch the clock at a certain time (ie 40 minutes), flip the power switch to ON. On the numeric keypad, enter “4” following by three “0”s. That will set the display to 40:00. When the official timers reach 40 minutes, push the CountUp button to start the clock counting up from 40:00.

When finished, push StopClock, then push Reset, and then flip the switch to OFF.

Big Clock Users Manual (3.2 MB pdf file)