Raymarine ST40 Service Manual page 23

Chapter 2, ST40 Depth Instrument
ST40 Instruments Service Manual 83149-2
When entering self test stage 3, the instrument beeps and the display shows TEST3,
for 1 second.
A transducer test then starts. If the interface is working correctly, PASS is displayed.
If the test fails, FAIL 43 is displayed. Use the following table to try to isolate the cause.
Check
Pulses at IC5, pins 1 & 4
Pulses at TR4 drain
Pulses at TR8 drain
Pulses at DEPTH+ & DEPTH-
Depth receiver output pulses
at IC4, pin 14
Press the and keys together momentarily to exit self-test.
Failure mode Action
No pulses Check R113
Check IC5 and replace if suspect
Check for dry joints at IC6 pins 46 & 49.
No pulses Check R123
No pulses Check R124
No pulses Check TR4, TR8 & T1
No pulses Return instrument to Raymarine Ltd.
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