Furuno TS-331A - Manual (Page 56)

7. MAINTENANCE & TROUBLESHOOTING
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7.3 Replacement of Internal Battery
A lithium battery on the Mother Board inside the Surface Processor Unit
preserves settings when the power is off. When the voltage of the battery is low,
the date and time will be wrong. When this happens, have a qualified technician
replace the battery, at your earliest convenience. Install the correct battery
properly (with correct polarity). Explosion may result if the wrong battery
type is used or the correct battery is installed improperly. Dispose of the
battery according to the appropriate regulations.
Part Type Code No.
Lithium Battery CR2032 000-129-884
7.4 Testing the Underwater Unit
If you feel the underwater unit is not functioning properly, conduct the test below
to check it for proper operation, using the test cable (supplied). Note that the test
may be conducted in air.
Required parts
• Test cable (supplied)
• Silicone spray
1. Turn off the Surface Processor Unit.
2. Open the underwater unit by unfastening six screws.
Unfasten six screws
(three more on opposite side)
Vertical Sonar
Transducer
Underwater unit