Sigma ONYX EASY Manual Del Usuario página 60

If no heart rate is shown on the display, this may
Important
be due to the following reasons:
note
k The belt with the heart rate transmitter is not
worn correctly
k The sensors (electrodes) on the heart rate
transmitter are dirty or dry
k Interference from electrical sources (high voltage
lines, railway cables, etc.)
k Transmitter battery (CR 2032) is dead
(Item no. 00342)
PAGE 28
Before starting to train, consult your doctor
to avoid risks to your health. This applies in
particular if you have cardio-vascular
problems.
7.5 Changing the
battery/waterproofing
and warranty
Special key for opening the battery
compartment.