SECTION FOUR — Troubleshooting and servicing the
No echoes displayed on sounder screen.
Is the
Advance YES Speed set to 
zero?
NO
Configure the navigatorʼs |
| Has the | |
NO | navigatorʼs | ||
Aux Port for the 491. See | |||
Aux Port been | |||
the “Initial checkout” |
| ||
| configured | ||
section of this manual. |
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| for the | ||
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|
| 491? | |
|
| YES |
1.Check fuses and circuit breakers.
2. Check power to 491 with | OFF | Check | STEADY | ||
a voltmeter. | GREEN | ||||
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3. Verify that the data cable |
| the 491's STAT |
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|
| ||||
| indicator |
| |||
between the navigator and |
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| |||
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the 491 is properly wired |
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| |
and connected. |
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| |
| FLASHING | RED |
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| GREEN |
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The 491 and the navigator aren't communicating properly. Check the wiring of the data 
cable between the navigator and the 491.
Change the Advance Speed setting.
491 is communicating with the navigator.
1.Check transducer connector for the proper wiring.
2.If wiring is correct,check transducer impedance with an ohmmeter.
3.If the transducer is open or shorted, replace it
There's a hardware problem with the 491.
Figure 13: 957/958/6000i echo sounder system troubleshooting
491 INSTALLATION MANUAL Revision A | PAGE 23 |