Fisher TW-7700 User Manual

TW-7700

Digital Line Tracer

Operating Manual

FISHER RESEARCH LABORATORY

CONTENTS

Description.............................................................................. pg. 3

Transmitter ............................................................................. pg. 4

Receiver ................................................................................... pg. 5

Accessories .............................................................................. pg. 7

Operating Instructions ......................................................... pg. 8

Depth Accuracy...................................................................... pg. 9

Specifications ......................................................................... pg. 10

DESCRIPTION

The TW-7700 Digital Line Tracer consists of a transmitter, receiver,
ground-plate/ground-rod assembly, carrying case (hard or soft),
and

an operators manual. The TW-7700 is a single frequency line tracer.

The TW-7700 is an active locating line tracer. There
are three methods of active locating that an operator
can use to trace a utility. The conductive method is
the most preferred method, since a strong transmitter
signal is transmitted through the intended target. The
inductive method is the easiest method to use, but
may not yield the best results. When a direct connec­tion is not available, but the operator has good knowl­edge of where one point of the utility may be, the op­erator can place the Transmitter over the utility mak­ing sure that the arrow on top of the transmitter is
parallel to the path of the utility. The third method of
active locating involves using the coupling clamp ac-
cessory. The coupling clamp is used when the utility is
exposed, but a direct connection is not available. The
clamp jaws are opened and placed around the utility.
The clamp never makes a direct connection with the
utility, that is, the utility can move freely with the
clamp around it.

The features of the TW-7700 make it a very easy and
practical instrument in today’s world of underground
locating.

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TW-7700 TRANSMITTER

Transmitter

Located on the transmitter are the power mode and
the accessory output. The power mode enables the
operator to turn the transmitter on or off, and to
check the condition of the batteries. When checking
the batteries, a reading if 50 or greater on the display
meter indicates that batteries are usable.

The accessory output is for the ground plate/ground
rod assembly, and for the coupling clamp. There is a
Red LED light that blinks when the transmitter is
on. The batteries are located underneath a lid on top
of the transmitter housing.

WARNING: Do not handle output leads unless power is off.
ELECTRIC SHOCK HAZARD: Servicing to be performed by

qualified personnel only.

The TW-7700 Transmitter.

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