Timex M821 User Manual

Page 7

S+D Sensor Battery Life and Replacement

The batteries in the S+D Sensor will last approximately 12 hours.
The S+D Sensor itself does not indicate the condition of its
batteries, except if the batteries are completely exhausted (as
noted in the section “Operating the S+D Sensor”). Instead, this
information is broadcast to your watch along with your perform-
ance data. Refer to the user manual for your watch for the proce-
dure to check the S+D Sensor’s battery level.

Replace batteries

• Remove the back cover of the S+D Sensor case. Lift and rotate

the latch ring a 1/4-turn counterclockwise to release cover.

• Remove old batteries and insert three new AAA batteries.

Observe the

markings inside the battery compartment to

ensure the new batteries are properly aligned.

• Replace S+D Sensor cover.

Maintenance

Rinse the S+D Sensor and its strap in fresh water periodically to
avoid buildup of materials that can interfere with the measure-
ment of your speed and distance.

Resolving S+D Sensor Errors and Error Messages

PROBLEM
• The S+D Sensor cannot lock onto GPS satellites (Indicator light

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 batteries 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.