Summary of Contents for Fisher Labs TW-7700
- Page 1 TW-7700 Digital Line Tracer Operating Manual F I S H E R R E S E A R C H L A B O R A T O R Y...
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Page 2: Table Of Contents
CONTENTS Description ................pg. 3 Transmitter ................pg. 4 Receiver ................... pg. 5 Accessories ................pg. 7 Operating Instructions ............pg. 8 Depth Accuracy ..............pg. 9 Specifications ................. pg. 10 Using Headphones..............pg. 11 Treasure Hunter’s Code of Ethics ........pg. 11... -
Page 3: Description
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. -
Page 4: Transmitter
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. -
Page 5: Receiver
TW-7700 RECEIVER Receiver The TW-7700 Receiver. Controls Mode This button does not have a function on the TW-7700. (It allows users of the TW-8800 Multi-Frequency Line Tracer to change frequencies.) Power On/Off Turns the receiver on or off. Light Lights up the display for usage in dark areas. When the display is backlit, LIGHT is shown on the bottom left hand side of the display screen. - Page 6 TW-7700 RECEIVER Display Frequency Modes The frequency at which the receiver is operating. << Left/Over Target>/Right>> Indicates where the receiver is in relation to utility. Numeric Display Serves a dual function: •Relative signal strength of the transmitted signal (% shown). Responds in conjunction with the bar graph.
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Page 7: Accessories
Fisher Research Laboratory has a variety of headsets avail- able. •Ultra-quiet deluxe Fisher Phones. High quality sound while reducing the outside noise. •Standard Stereo Headphones •Single Earpiece Headset. Enables the operator to effec- tively listen to the TW-7700 and remain aware of noise in close proximity. -
Page 8: Operating Instructions
OPERATING INSTRUCTIONS The following instructions are designed for a safe and effective method of line tracing and utility avoidance. Some of the steps may not be applicable in all situations. The underlying guide- line is that operator safety must be maintained at all times. Use of safety equipment, extra personnel, and up to date as-built plans should be considered when necessary. -
Page 9: Depth Accuracy
DEPTH ACCURACY Depth measurement is a feature of the TW-7700. Accuracy is defined on an ideal target, that is, one that is continuous, a good conductor, and not surrounding by other utilities. There are factors that can cause the operator to question the accu- racy of the utility being traced. -
Page 10: Specifications
SPECIFICATIONS Subject to improvement or modification without notice. RECEIVER Depth Accuracy ......+1 inch per foot in nominal conditions Readout Units ......Inches or cm (factory preset) Left/Right Guidance ....Audio: continuous tone=Left, pulsed tone=Right. VCO (varying pitch) output for easy over .......... -
Page 11: Using Headphones
USING HEADPHONES Using headphones (not supplied) improves battery life, and prevents the sounds from annoying bystanders. It also allows you to hear subtle changes in the sound more clearly, particularly if searching in a noisy location. For safety reasons, do not use headphones near traffic or where other dangers are present. - Page 12 Q U A L I T Y Fisher detectors are renowned for their quality. Each detector is hand crafted in the USA with pride P E R F O R M A N C E The worldwide underground utility industry relys on Fisher. Our instruments are durable, dependable, and locate deeper.