Desco 19250, Technical Bulletin

Page: 5 / 7

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • (909) 627-8178
DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • (781) 821-8370 • Website: Desco.com
TB-2040 Page 5 of 6
© 2013 DESCO INDUSTRIES INC.
Employee Owned
Observe the LEDs for the proper response as indicated. Be sure
to hold the cord at an insulated point, so that resistance value is
not affected by the body. Should testing reveal that the Tester is
not functioning properly, verify that the battery or power supply is
operating correctly.
Tester calibration can also be verified with the use of discrete
resistors and two banana-to-alligator cords.
Adjustment
Detailed adjustment instructions follow:
Equipment Required: - Small blade screwdriver or Trimpot
adjusting tool, manufacturer’s calibration box or a resistor decade
box or discrete resistors, with appropriate test leads.
PREPARATION OF THE UNIT:
Make sure that a fresh 9 Volt alkaline battery is installed, and
orient tester so that it corresponds to Figure 15.
RANGE FAIL LO PASS LO PASS HI FAIL HI
WRIST STRAP 675K 825K 8.5M 11.5M
FOOT WEAR 675K 825K 80M 120M
RESISTANCE “A” “B” “C” “D”
CALIBRATION OF FOOT WEAR RANGES:
1. Connect resistance “A” from table 1 or 2, this time between
the test button and the “FOOT PLATE” banana jack on the
left side of the tester. For footwear calibration, press and
hold the touch plate. The red “FAIL LO” LED should be on.
2. If required, adjust
FWL
trimpot to the point where the “FAIL
LO” LED illuminates.
3. Connect resistance “B” and press switch as in step 1. The
green “PASS” LED illuminates. The
FWL
trimpot may
require a slight re-adjustment.
4. Connect resistance “C” (
footwear range
) and press switch as
in step 1. The green “PASS” LED should illuminate. If
required, adjust the
FWH
trimpot to the point where the green
LED illuminates.
5. Finally, connect resistance “D” (
footwear range
) and press
switch as in step 1. The red “FAIL HI” LED should illuminate.
The
FWH
trimpot may require a slight re-adjustment.
6. Re-check to insure that all footwear ranges are correct.
RETURN UNIT TO SERVICE .
Unauthorized modifications will void the product warranty.
Servicing should be performed only at the factory. See warranty
section for repair information.
Specifications
Wrist Strap Circuit
FAIL HI Factory set at 11.5 Megohms
FAIL LO Factory set at 675 Kilohms
Footwear Circuit
FAIL HI Factory set at 120 Megohms
FAIL LO Factory set at 675 Kilohms
General Characteristics
Power 9 Volt battery or optional AC power supply
Operation Resistance bridge
Readout Three LED’s & audible alarm
Accuracy ±20%
Weight 12 pounds
Height 39 inches
Consider adding the 19250 to your list of “test equipment [that]
shall be selected to make measurements of appropriate properties
of the technical requirements that are incorporated into the ESD
program plan” as required by paragraph 6.1.3.1 of ANSI/ESD
S20.20.
Figure 15 . Back of the Combo Tester
CALIBRATION OF WRIST STRAP RANGES :
1. Connect resistance “A” from Table 1 OR 2 between the touch
plate and the “WRIST CORD” banana jack. A banana plug
must be inserted in the banana jack to properly test the
wrist strap ranges. Press and hold the test button. The red
“FAIL LO” LED should illuminate.
2. If required, adjust WSL trimpot to the point where the “FAIL
LO” LED illuminates.
3. Connect resistance “B” and press the switch as in Step III.
The green “PASS” LED should illuminate. The WSL trimpot
may require a slight re-adjustment.
4. Connect resistance “C” ( wrist strap range ) and press the
switch as in step 1. The green “PASS” LED should be on. If
required, adjust the WSH trimpot to the point where the green
“PASS” LED illuminates.
5. Finally, connect resistance “D” ( wrist strap range ) and press
the swtich as in step 1. The “FAIL HI” red LED should be
on. The WSH trimpot may require re-adjustment.
6. Re-check to insure that all ranges are correct, then proceed
to calibrate footwear ranges.
TABLE 1 - STANDARD RANGES