Replacement Of Backup Battery - Furuno FELCOM 12 Service Manual

5.7 Replacement of Backup Battery

The life of the lithium battery on the CPU board is about five years. The longer the time
when the unit is off, the shorter the life of the battery.
U11 (M6M80041P): EE-PROM
Forward/Return ID programmed
BACK UP
• U40 (SRM20100LLM70): SRAM
• U36 (RTC62423): TIMER
• Battery Type: CR 1/2 8L-F
• Code Number: 000-103-769
Note) Remove JP1 when replacing the battery soldered. The settings backed-up by the
battery is listed on page 5-7. The figure below shows the outline of memory back-up
circuit.
BT1
TP1
U11: EE-PROM
BUZZER
BATT
JP1
BACK UP ON/OFF
Figure 5-5 CPU Board
U17
JP1
VBAT
VOUT
VBAT
(CPU
monitor)
CPU (16P0148)
Figure 5-6
5-11
TP3 TP2
U44: DEMOD
ROM
U39: ROM
U36
TP4 TP5
S1
U40
U40
(SRAM)
U36
(RTC)
J8-5
GN-74
(GPS)
CR 7
CR 8
CR 9