TO OPERATE:  Insert the plug from the transducer element into the PROBE INPUT jack.   Insert the headset plug into the HEADSET jack. BE CAREFUL!  Don't get the right plug into the wrong jack.   The gray headset tube is worn UNDER the chin with the two sound output holes facing slightly (30 degrees) forward.   Hold the transducer firmly on the surface being tested and adjust the GAIN as desired.

A single 9 volt battery (Alkaline preferred) powers the 4020.   Normal battery life is approximately 100 hours of ON time.  As with any battery operated equipment, remove the battery during periods of prolonged storage.

Treat this piece of equipment as you would any other sophisticated electronic equipment.   The transducer element is an ultra sensitive piezo-crystal and represents the best compromise between performance and ruggedness. It is, however, sensitive to severe shock so dropping the probe on a hard surface will probably damage the element.  Do not expose to temperatures in excess of 120 degrees F for long periodme. Remember, the glove compartment or trunk of a car can easily exceed this limit on a bright sunlit day. Use common sense.

To replace the battery, loosen the two cover screws one or two turns counterclockwise and, with the lettered side down, carefully remove the back cover. Remove the old battery and replace with a fresh one (Alkaline always preferred). Replace the cover being careful not to pinch the battery leads and tighten the screws (do not over-tighten).