SECTION THREE — Installing the 491
1/2” Max. 
#1 Speed Signal |
|
| #2 Speed +V |
|
#4 Thermistor | 1 | 2 | #3 Speed Gnd |
|
#5 Depth 50 kHz + |
| 3 | #7 Thermistor |
|
4 5 | 6 7 |
| ||
#8 Depth 200 kHz + | 8 | 9 | #6 Depth 50 kHz – | Wire stripping detail |
#10 Depth 200 kHz – |
| 10 | #9 Depth Shields | |
|
|
|
|
3/16”
FIGURE 10: Wiring of B260 transducer cable (solder-cup side of connector
shown)
1/2” Max. 
#1 Speed Signal |
|
| #2 Speed +V |
|
#4 Thermistor | 1 | 2 | #3 Speed Gnd |
|
#5 Depth 50 kHz + |
| 3 | #7 Thermistor |
|
4 5 | 6 7 |
| ||
#8 Depth 200 kHz + | 8 | 9 | #6 Depth 50 kHz – | Wire stripping detail |
#10 Depth 200 kHz – |
| 10 | #9 Depth Shields | |
|
|
|
|
3/16”
FIGURE 11: Wiring of B44/B744 and P66 transducer cable (solder-cup side of
connector shown)
Initial checkout
Turning the 491 on
Plug the transducer cable into the TRANSDUCER connector of the 491.
If your transducer doesn’t support speed, you can connect a separate speed sensor, such as the Airmar ST650, to pins 1, 2 and 3, as shown in the table.
This section assumes that the 491, Northstar navigator, and transducer are now all properly connected. Turning on the navigator automatically turns on the 491 (be sure your vessel is in the water). To turn the naviga- tor on, briefly press its PWR key.
For the 961/962
To use the 491 echo sounder, the 961/962 must be running software ver- sion 3.0 or higher. If not, contact the factory to obtain the upgrade CD. To install the upgrade, follow the steps on the back of the jewel box.
You must set the 961/962’s Port 3 to “490”:
1.Press STAR to display the SERVICE MENU screen.
2.Press PORT SETUP.
3.Press PORT 3.
4.Set the FORMAT option to 490.
The STATUS indicator light on the 491 glows steady green when the 491’s power is on.
491 INSTALLATION MANUAL Revision A | PAGE 19 |