NorthStar 972 Quickstart Manual And Reference Manual page 128

Troubleshooting the echo sounder
Step Decision Point
Has the AUX port been
1
configured for the 491?
Is the Advance Speed set to
2
zero?
Is the 491's LED STAT indi-
cator dark?
3
Is the LED blinking or
steady on?
4
Is the LED flashing once
per second or four times
5
per second?
Reference section 7 — Echo sounding
124
Troubleshooting the echo sounder
If there are no echoes displayed when the
shooting table to determine the cause.
If No, follow the steps in Setting
up the echosounder, on page 151.
If No, proceed to step 3.
If No, proceed to step 4.
If Flashing, proceed to step 5.
If Four times per Second, there is
most likely a hardware problem
inside the 491.
SOUNDER
Condition 1
key is pressed, follow this trouble-
Condition 2
If Yes, proceed to step 2.
If Yes, change the Advance speed set-
ting.
If Yes:
Check fuses and circuit breakers.
Check power to 491 with a voltme-
ter.
Verify data cable is properly wired
and connected.
If Steady On:
Check transducer connector for
proper wiring.
If wiring is correct, check transducer
impedance.
Replace transducer if open or
shorted.
If Once per Second, the 491 and the
972 are trying to establish communi-
cation.
Wait two minutes, then check all wir-
ing to the 491 and try again.
Northstar 972