Advanced Marine Electrics and Electronics Troubleshooting A Manual for Boatowners and Marine Technicians

marine troubleshooting 9

NEW METHOD

OLD METHOD

SYMPTOM

AC Resistive Loads (4)

Perform a waveform analysis using an oscilloscope (Chapter 7).

Without an oscilloscope, there is no efficient way to perform this task.

Equipment operates

fine on shore power

but malfunctions when

powered by an inverter

or generator.

• Diagnose waveform and harmonics
  issues: use an oscilloscope (Chapter 7);
  if a problem is intermittent, use an
  oscilloscope/laptop combination to
  track and record data (Chapter 8).


• For safety reasons, routinely use a Yoko-
  gawa or similar clamp-on leak tester
  (Chapter 10).

Flowcharts: Electronic Devices

Here we’ll cover circuits serving electronic
equipment, such as audiovisual, navigation,
and communications devices:

• autopilots


• communications equipment—VHF and
  SSB radios


• computer or laptop


• depth sounders


• fishfinders and chartplotters


• navigational equipment—GPS and radar


• stereo systems


• televisions and DVD players


• weather monitoring equipment

This category is a bit more complicated

than electrical systems because it includes

both AC- and DC-powered gear, with

slightly different considerations for each. As

with all devices, the first step is to confirm

the integrity of the power source at the

device. In the case of these circuits, that

means voltage, whether it’s 120 VAC (volts of

alternating current) or 12 or 24 VDC (volts

of direct current). In many cases, however,

you may need to take additional steps.

The troubleshooting procedure for naviga-

tion and communications equipment is sum-

marized in the flowcharts on pages 11 and 12.

For troubleshooting audio and video systems

powered by AC current, see the bottom flow-

chart on page 12.

Inverter AC output*: Perform a waveform analysis to look for harmonic

distortion that may affect the equipment. Use a true RMS multimeter** or,

preferably, an oscilloscope (Chapter 7).

*Ideal Industries does not recommend using the SureTest (Chapter 4) on inverters,

but I have used it successfully on true-sine-wave inverters.

**True RMS multimeters are discussed in the Powerboater's Guide to Electrical

Systems. Simply put, true RMS describes the algorithm a meter must have to

accurately analyze a less than perfect AC waveform. Most common meters use an

average responding algorithm.

Using a conventional multimeter, perform multiple steps using a “split” shore cord adapter to take voltage and current

measurements in the hot, neutral, and ground conductors. This method doesn’t have the advantages of data logging.

NEW METHOD

OLD METHOD

Equipment operates

fine on shore power

but malfunctions when

powered by an

inverter.

Battery Chargers and Inverters (1)

SYMPTOM