3M 746 Watch User Manual

158 x 95 x 33 mm (6.25 x 3.75 x 1.25 inches)

200 g (7 ounces) without battery


750 k + 20%/-0%, 10 M 10%

Note: In some cases, high contact resistance between the person's skin and wrist band will cause the tester to show a fail/red LED condition. This resistance may be caused by dry skin or hair in the wrist area. If these possibilities do not match to the operator, the wrist band should be replaced.

Measurement Voltage:

DC (191) V (open circuit)

Power Supply (not included):

DC 9V, regulated, 75mA (50Hz)

5.0 How to Use

Insert 9V battery and make sure the ON/OFF switch at the upper left side on the unit is in the ON position. The OFF position avoids discharge of the battery if the metal contact plate is accidentally depressed while the unit is not in use. The unit is then ready for operation. The backup of the battery can be achieved by using an AC Power Supply. In that case, connect the

AC power supply to the jack at the base of the unit. Plug the power supply into an AC 230V

Wall Mounting

Fit the plastic cover onto the wrist strap plug-in jack that is not being used. If the "battery" LED illuminates, replace it immediately.

Put the wrist band on with ground cord attached, and insert the ground cord plug into the wrist strap plug-in jack.

Depress the metal contact plate and hold it.

One of the indicator LEDs will illuminate.

An illuminated green LED indicates that the wrist strap performs within the resistance range of 750 k to 10 M. If a "red" condition is indicated, it is advisable to check the ground cord individually for its resistance.

The enclosed 3M Dual Lock adhesion discs shall be screwed on the wall using the attached template approximately 1500 mm (5 feet) parallel off the floor. Drill three holes of 5 mm

(0.2 in) diameter at marked location.

The enclosed 3M Dual Lock adhesion strips must

be adhered to the rear of the 3M Wrist Strap

Tester 746 parallel to the bottom edge and below the battery compartment.

Note: Make sure the area on the unit in which the Dual Lock adhesion strips are placed is free of dust and dirt. Press the tester firmly against the discs for fixing on the wall.

Wrist Strap Test

If the "battery" LED illuminates at any time, replace the battery.

For removal, lift the tester 746 at the two top corners with both hands.


6.0 Calibration Procedures

Wrist strap test circuit check:

The 3M Wrist Strap Tester 746 cannot be adjusted, but the following steps can be used to determine that the tester is operating within its specification.

Connect the resistance substitution box to the 746 as shown in figure 2.

Set the resistance substitution box to each value of resistance indicated in the test table and