Timex M640 Heart Rate Monitor User Manual


 
11
is broadcast to your watch along with your performance data.
Refer to the user manual for your watch for the procedure to
check the S+D Sensor’s battery level.
Replace battery
• Flip out the half-circle handle on the battery hatch (located on
the side of the S&D Sensor case) and turn it counter-clockwise
to unscrew.
• Remove the battery hatch.
• Remove old battery and insert one (1) new AA battery. Observe
the +/- markings inside the battery compartment to ensure the
new battery is properly aligned.
• Replace the battery hatch and tighten the cap by turning clock-
wise. Do not over-tighten.
Maintenance
Rinse the S+D Sensor and its strap in fresh water periodically to
avoid buildup of materials that can interfere with the measurement
of your speed and distance.
Resolving S+D Sensor Errors and Error Messages
PROBLEM
• The S+D Sensor cannot lock onto GPS satellites (ON/OFF button
never changes to flashing green).
• The GPS S+D Sensor loses signals from the satellites during use.
The watch may display a message that the GPS signal is weak.
SOLUTION
• Move to a more open outdoor area.
• Move away from metal objects.
• Replace the battery in the S+D Sensor.
NOTE: The system can maintain accuracy for short periods when
GPS signals are lost.
PROBLEM
• Watch displays FATAL GPS ERROR message.
SOLUTION
• The S+D Sensor is damaged; contact Timex Customer Service.
S+D Sensor Battery Life and Replacement
The battery in the S+D Sensor will last approximately 12 hours.
The S+D Sensor itself does not indicate the condition of its
battery, except if the battery is completely exhausted (as noted in
the section “Operating the S+D Sensor”). Instead, this information
10