Keysight Technologies E4360 Series, Service Manual, Page: 54 / 75

5 Troubleshooting
54 Series E4360 Service Guide
Front Panel Troubleshooting
Troubleshooting the front panel board involves checking for the
presence of the correct bias voltages on the board. Refer to the following
table and figure.
Test Point Location Voltage Action
TP 1 BKL_VCC +12 V If bias not present, troubleshoot the bias board or replace
the front panel board.
TP 2 P1 pin 3 +12 V If backlight voltage not present, replace the front panel
board.
If voltage is present and the display is not lit, replace the
display.
Common GNDB Common
Bias Board Troubleshooting
Troubleshooting the bias board involves checking for the presence of the
correct bias voltages on the board. Refer to the following table and
figures.
Note that if the bias voltages at test points 2 - 4 in the following table
are not present, it could be caused by a defect in the output module or
interface board that is pulling the bias voltage low.
Test Point Location Voltage Action
TP 1 + RED +48 V Output of bulk supply. If not present, replace the bulk
supply.
TP 2 + C4 +12 V If biases at TP 2, TP 3, or TP 4 are not present, disconnect
the backplane and interface board cable assemblies and
recheck. If biases are still not present, replace the bias
board.
TP 3 U9 - 2 +5 V Same as above.
TP 4 + C3 +3.3 V Same as above.
Common −
BLK
Common