– 18 –
allow one minute for the source to stabilize. Note if the reading on the display is
within ± 10% of the test cable calibration value. A reading outside this range can
be caused by drift of the LED from aging or large changes in room temperature.
To restore the factory setting or establish a different power level proceed with the
following steps.
5.
Locate the rectangular potentiometer (it has a small screwdriver slot) on the
circuit board area closest to the LED receptacle as shown in Figure 4. With the
LED source on and stable, adjust the LED drive current (controls the power)
by turning the potentiometer slot with a small blade screw-driver. Clockwise
rotation will increase the current, and vice-versa. Adjust the potentiometer
until the display reads within ± 10% of the calibration value supplied with the
test cable.
Note: DO NOT ADJUST ANY OTHER POTENTIOMETER ON
THE CIRCUIT BOARD SET EXCEPT THE ONE DESCRIBED. Doing so
will destroy factory calibration of the radiometer portion of the test set,
requiring the unit to be returned for service.
6.
If a different power level is desired, adjust the potentiometer until the display
reads an appropriate fraction of the calibration value. For example, if you want to
double the LED power from the factory setting, adjust the potentiometer until the
display reads double the calibration value. To restore LED power to the factory
setting, simply adjust the drive current until the display reads the test cable
calibration value.
7.
After the adjustment is made, turn off the test set power by pressing the “ON/
OFF” switch. Remove the test cable and place the front panel back onto the
chassis. Replace the four screws in the corners of the front panel and tighten them
securely.
Malfunctions
In the unlikely event that the meter malfunctions, you may have it repaired by doing the
following:
• In writing, describe the problem, name of the person whom we should contact,
phone number, and an appropriate return address.
• Zero adjustment is needed. Follow the “Zeroing” Procedure in the section titled
SERVICE AND MAINTENANCE.
• Pack the Fiber Optic Test Set, test cable, manual and your letter carefully in a
strong box with adequate packing material to prevent damage in shipment.
• Ship the package to:
I
NDUSTRIAL
F
IBER
O
PTICS
1725 W
EST
1
ST
S
TREET
T
EMPE
, AZ 85281-76222
USA
