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

$60 to $100 range. TDRs, on the other hand,

are not quite as basic. The alphanumeric unit

described in this chapter costs about $500.

The time it can save in troubleshooting prob-

lems, however, more than justifies its price.

Warning: You should trace only unener-

gized wiring. Contact with live circuits can

result in severe injury or death. Always dis-

connect power to the circuit before using a

circuit tracer.

38 electrical systems troubleshooting

tracer (receiver)

signal-generating transmitter

Next we’ll look at how these tools are used

for tracing wires through boats, finding open

circuits or breaks in wires, and in the case of

the TDR, how far down a wire run the break

or short circuit is located.

Tone-Generating Circuit Tracer

A tone-generating circuit tracer has two com-

ponents: a transmitter, and a handheld receiver

or tracer. The transmitter, connected by its dual

leads to a pair of cables routed together, sends

an oscillating signal down the length of one of

the conductors. Most units operate in a fre-

quency range between about 800 Hertz (Hz)

and 1,100 Hz. This signal bounces, or reflects,

off the parallel cable, something like radar. The

receiver unit’s pointed end detects this reflected

signal and amplifies it so that you can hear it.

(Most units also have a small light built into the

receiver that glows as it senses the signal.) By

moving the receiver down the length of a wire

run, you can effectively trace the signal across

the conductor’s entire length. If the receiver

suddenly stops producing audible and visual

signals, an open circuit or break is implied.

Right there you may have found the source of

your electrical problem.

You must have access to the entire wire run

and be able to track down the entire length of

the harness to find a break. Unfortunately, you

The Wire Tracker tone-generating circuit tracer (left) is sold in the United
States by Ancor Marine. It is really two devices: a signal-generating
transmitter and a handheld tracer or receiver. The Fault Mapper model
CA7024 alphanumeric TDR (right) is made by AEMC Instruments.

Wire Tracker, Ancor Marine, http://www.ancorproducts.com

Fox and Hound, Triplett, http://www.triplett.com

TR02 Cable Tester, AEMC, http://www.aemc.com

TONE-GENERATING CIRCUIT TRACERS