Raymarine ST40 - Page 23

Chapter 2, ST40 Depth Instrument
ST40 Instruments Service Manual 83149-2 2-11
E22038
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 Failure mode Action
Pulses at IC5, pins 1 & 4 No pulses Check R113
Check IC5 and replace if suspect
Check for dry joints at IC6 pins 46 & 49.
Pulses at TR4 drain No pulses Check R123
Pulses at TR8 drain No pulses Check R124
Pulses at DEPTH+ & DEPTH- No pulses Check TR4, TR8 & T1
Depth receiver output pulses No pulses Return instrument to Raymarine Ltd.
at IC4, pin 14
Press the and keys together momentarily to exit self-test.