Furuno FR-2115-B Installation Manual page 47

4.2.2 ARP board adjustment
1. Turn the GAIN, A/C SEA and A/C RAIN controls fully counterclockwise (OFF). Transmit on
the 12 nm range.
2. Connect a digital multimeter between TP7(+) and TP6(-) on the ARP Board.
3. Adjust R104 on the ARP Board so the multimeter reads between 0.09 and 0.14 VDC.
4. Set controls and switches as below.
5. GAIN: fully clockwise (max.)
Interference rejector: OFF
Range: 24 nm
Echo stretch: OFF
6. Press [RADAR MENU] [0] [0] [0] [2] [0] to open the INITIAL SETTING2 menu.
7. Set the VIDEO SIG field to DIGITAL and press the [ENTER] key.
8. Adjust R103 on the ARP Board so noise just appears on the display.
Too little noise
9. Set VIDEO SIG to ANALOG and press the [ENTER] key.
TP6
R104
TP7
Figure 4-6 ARP Board (18P9002B)
Proper noise
Figure 4-7 How to adjust noise
R103
4-8
Too much noise