Suppressing Main Bang - Furuno FR-1500 MARK-3 Series Installation Manual

VIDEO SIGNAL
Video Level
Approx. 4.0 Vpp ±0.2 V
Gate for video
adjustment
Timing Correct

5.6 Suppressing Main Bang

If main bang appears at the screen center, suppress it as follows:
1. Transmit on a long range and then wait ten minutes.
2. Adjust the GAIN control to show a slight amount of noise on the display.
3. Select the 0.25 nm range. Adjust the A/C SEA control to suppress sea clutter.
4. Press [MENU] [0] [0] [0] [0] [5] [5] [5] to select MBS-T from the SET UP 1
menu.
5. Adjust the VRM control to adjust MBS timing (Adjustable range: 0-127).
6. Press the [ENTER/SELECT] key.
7. Press the [6] key to select MBS-L (MBS-Level).
8. Adjust the VRM control to adjust MBS level (Adjustable range: 0-127).
9. Press the [ENTER/SELECT] key.
Main Bang
Adjust the EEPOT (U92) on the pcb 03P9230 so average
video level is 4.0 Vpp ±0.2 V during this interval.
Figure 5-7 Video signal timing
Video Level
Approx. 4.5 Vpp
Timing Wrong
5-5