Atec Fluke-LS-1310-1550 - Manual (Page 7)

Service Information Sheet
Calibration Adjustments for Serial Numbers
≥
79130000
7
1-6. Before applying power to the laser source, do
the following:
a. Adjust the internal potentiometers R39
and R40 to their full counterclockwise
positions. You will hear a faint click at
the full counterclockwise position.
b. Adjust the external OUTPUT ADJUST
potentiometers (R12 and R31) to their full
counterclockwise positions. You will hear
a faint click at the full counterclockwise
position.
1-7. Adjust the dc power supply to 9 V ±0.25 V
with the output current limited to 250 mA.
Connect the power supply’s positive lead to
BT1+ on the laser source, connect the
negative lead to BT1-.
1-8. Set the laser source's CW/MOD switch to the
CW position.
1-9. Set the laser source's power switch to either
the 1310 nm or 1550 nm position. Verify that
the laser source
LOW BATTERY LED is off
and the SOURCE ACTIVE LED is on.
Step 2: Checking the Laser Drive
Voltage
Use the following procedure to check the drive
voltage for the laser diodes and to verify that the
laser source's low battery detection circuit is
operating properly.
2-1. Connect negative probe of DMM to TP2
(Gnd).
2-2. Turn laser source to either 1310 nm or
1550 nm, set the CW/MOD switch to the CW
position.
2-3. With the DMM verify the voltage of Z5 pin 8
is 1.23 V ±0.04 V.
2-4. Check the voltage on the plus (+) side of C13,
verify it is 5 V ±0.2 V.
2-5. Decrease the power supply voltage just until
the laser source's
LOW BATTERY LED is lit.
2-6. Verify the power supply voltage is 5.9 V
±0.2 V.
2-7. Reverify voltage on plus (+) side of C13 is
5 V ±0.2 V.
Step 3: Calibrating and Adjusting the
1310 nm Circuit
Use the following procedure to make calibration
adjustments to the 1310 nm laser diode circuit:
3-1. Adjust the dc power supply to 9 V ±0.25 V
with the output current limited to 250 mA.
Connect the power supply's positive lead to
BT1+; connect the negative lead to BT1-.
3-2. Set up the DMM to measure dc volts less than
2 V. Connect the negative probe to TP2 (Gnd)
and the positive to the side of R20 furthest
from Z2. To calculate current in the 1310 nm
laser drive use the equation I = V/22.
3-3. Use a singlemode fiber patch cable to connect
the laser source to the OPM. Set the OPM to
measure 1310 nm.
W
Caution
In the following steps, do not exceed
the laser diode’s maximum operating
current of 60 mA. Doing so can damage
the laser diode. If the current reaches
60 mA before the optical power reading
reaches -9.2 dBm, clean the ST
connectors or repair the laser source.
3-4. Set the laser source to 1310 nm. Turn R12 to
full clockwise position.
W Caution
In the next step, slow the adjustment
rate on R39 as the optical power reading
approaches
-14 dBm. If you turn R39 too quickly,
you might overshoot the -9.2 dBm target
and exceed the laser diode’s maximum
current of 60 mA.
3-5. Adjust R39 clockwise until either the power
reading is -9.2 dBm ±0.1 dB or the current
reaches 60 mA. A typical current value is
15 mA at -9.2 dBm. If the current reaches
60 mA before the power reading reaches
-9.2 dBm, the laser source requires repair.
3-6. With the laser source set to 1310 nm, verify
that the power reading is -9.2 dBm ±0.1 dB.
3-7. Adjust the 1310 nm external potentiometer
(R12) counterclockwise to verify that the
laser source output is adjustable to -11.2 dBm
±0.1 dB.
3-8. Adjust R12 until the laser source output reads
-10.0 dBm ±0.1 dB.