How do you calibrate fmc 4100 wheel balancer?

1. Press F1 and SPIN 2. The display will read "CAL Slu". Attach the round calibration weight (stored on the back of the machine near the power switch) in the threaded hole on the outer edge of the balance shaft flange. 3. Press SPIN again or lower the Wheel Guard to initate the balancer spin cycle. The shaft will turn for about 15 seconds. 4. The display will then change to "CAL 0". Remove the calibration weight and Press SPIN or lower the wheel guard to perform the second step of calibration. 5. After another 15 seconds of spin the display will read "CAL Good" to indicate a good calibration. The operators with this information can be download from: http://www.snaponequipment.com/common/op-manuals/jb/past-products/4100_om.pdf Also, make sure the device is on a very stable surface like concreate. Wood floors will allow the machine to move during balance and can produce a tire that is out of balance even if the machine says the balance is good.