Agilent Technologies 87075C Option H08, User'S And Service Manual

Page: 54 / 66

52 Chapter 4
Service
Troubleshooting
Troubleshooting
This section contains information on troubleshooting the test set to the assembly level
only. By following these procedures you should be able to determine whether the power
supply, front panel, or main switch board needs replacing. A block diagram is included at
the end of this section as an aid in troubleshooting.
The theory of operation information can be found starting on page 55 .
General Troubleshooting Notes
WARNING
Always turn the instrument power Off before removing or
installing an assembly.
WARNING
Some parts in the instrument have sharp edges. Work carefully
to avoid injury.
CAUTION
If you need to disassemble the instrument, be sure to work at an
antistatic workstation and use a grounded wrist strap to prevent
damage from electrostatic discharge (ESD). See
“ESD Protection Setup”
on page 15 .
NOTE
Before replacing an assembly or board, inspect for obvious, easily
repaired defects such as bent pins on ICs or cold solder joints.
Troubleshooting Power Supply Problems
Turn the instrument on. Check the condition of the LED on the front panel:
1. If the LED is off, check the main fuse located in the power supply filter at the rear of
the instrument.
2. If the fuse is in working order and the LED is still off, check the cable and connections
between the main board and front panel board.
3.
If the cable and connections are working and the LED is still off, there is still a
possibility that the power supply is not supplying the nec15 V, –15 V, and +5 V
to the main board.
Disconnect the dc power cable from the power supply to the main switch board and
measure the voltages. They should be +15 V,
–15 V, and +5 V. If not, replace the power supply.