Agilent Technologies 83438A - Manual (Page 68)

5-14
Servicing
Troubleshooting
If the output power is low
1 Check for the following common problems:
❒ Check that the front-panel ACTIVE key is on. If the ACTIVE or LINE LEDs do not
light, refer to “To check the A4 Power Supply Board Assembly” on
page 5-18.
❒ Clean the OPTICAL OUT connector as described in “Cleaning Connections for
Accurate Measurements” on page 2-11.
❒ Remove any modulating signal from the rear-panel MODULATION INPUT con-
nector. Modulation reduces the average output power. Of course, the de-
crease in power is tied to the duty cycle of the modulating signal.
❒ Check the rear-panel MODULATION INPUT connector. If a BNC short is con-
nected, the output is turned off.
2 Perform the adjustment procedure “To adjust total power” on page 5-24.
Confirm that the power is low and cannot be adjusted within the specification.
3 Perform the procedure “To check the A4 Power Supply Board Assembly” on
page 5-18.
4 Perform the procedure “To check the A5 Laser Driver Board Assembly” on
page 5-15.
5 Perform the procedure “To check the A2A2 Laser Modulation Board Assembly”
on page 5-17.