Humminbird 4000 User Guide

 

indicating more sensitivity. In 
shallow water or when a hard 
bottom is being read, the 
sensitivity needed to achieve a 
good return will be less. Also in 
the automatic mode, the unit will 
black out the display beneath the 
bottom line. 

 

Manual Mode- There are two 
ways of putting the LCR4000 in 
the manual mode: (1) depress 
the Auto "On/Off" button or (2) 
depress either sensitivity 
decrease (-) or increase (+) 
button. You will notice that the 
word Auto in the upper right hand 
corner of the display has gone 
off. The operator can control the 
amount of sensitivity by 
depressing the (+) or (-) button. 
There are 15 sensitivity settings. 

When the (+) or (-) button is pressed 
once, the sensitivity setting at the top 
of the screen will change by one 
division. If the (+) or (-) button is held 
down the setting will move up or down 
as long as the button is held down. 
When the maximum or minimum 
setting is achieved, the unit will make 
a “Chirping" sound indicating a limit 
has been reached. 
 
In the manual mode everything below 
the bottom is no longer blacked out, 
therefore a second return or double 
echo can be displayed if desired. (See 
Figure 14). Also, the hardness of the 
bottom can be determined by the 
thickness of the bottom return. For 
example, a hard or rock bottom will 
give a wider bottom return as 
compared to a soft or muddy bottom. 
(See Figure 15).