Furuno SC-50/110 Fish Finder User Manual


 
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6. Maintenance
6.1 Adjustment
1) PWR board
Switching regulator frequency is adjusted on PWR board, 20P8181 as below.
Test Point GND Rating Adjuster
TP2 TP1 120.0 kHz ± 10 kHz VR79
TP5 TP3 120.0 kHz ± 10 kHz VR80
2) MAIN board
Vcc-c supply voltage to Rate sensor is adjusted by VR96 on MAIN board, 20P8178.
Test Point GND Rating Adjuster
#1 of J20 #2 of J20 5.0 V (Vcc-c) VR96
6.2 Line voltage check
Line voltages are checked at J3 on the MAIN board.
Line voltage Test Points on MAIN board Rating
3.3 V #4 (+) and #5(-) of J3 3.15 to 3.45 V
5.1 V (5 V) #1 (+) and #5(-) of J3 4.94 to 5.46 V
6.5 V #8 (+) and #5(-) of J3 6.2 to 6.8 V
13.5 V (15 V) #7 (+) and #5(-) of J3 12.5 to 14.4 V
6.3 Jumper setting
Jumper JP1 on the MAIN board is used at factory to set the MAIN board to A or B version.
6.4 LED
CR3 on the MAIN board blinks when the CPU is running.