Troubleshooting With The Service Screen - Agilent Technologies E8285A Manual

Service Screen

Troubleshooting with the SERVICE Screen

Troubleshooting with the SERVICE Screen
The SERVICE screen, see
voltmeter and frequency counter functions to monitor specific nodes in
most assemblies. A large number of latch and DAC settings used
throughout the Test Set can also be read and/or set to alter standard
operation. These functions are primarily intended to allow the
automated internal diagnostic routines to verify proper instrument
operation, and to allow the periodic adjustment routines (PER_CAL3,
CDMA_CAL, and PCB_CAL) to modify Test Set operation.
Access to these functions under manual control is provided to allow
further troubleshooting when the diagnostics cannot isolate a failure to
a specific assembly. To do this, you must understand how to operate the
Test Set and, especially, understand how the assemblies in the Test Set
work together.
Detailed manual Test Set operation is provided in the Agilent
Technologies E8285A User's Guide. Refer to
Diagrams," on page 249
and each module work.
How to Access the SERVICE Screen
1. Press Preset key.
2. Press the Config key on the Test Set to access the CONFIGURE
3. Select the SERVICE field in bottom-right corner of the screen.
Field Names and Descriptions
Voltmeter Connection
This field (see
measurements. To change the voltmeter connection, move the cursor in
front of the Voltmeter Connection field and push the cursor control
knob. A Choices menu will appear. Move the cursor to the desired
circuit node in the list and push the cursor control knob. The reading is
displayed in the Voltage measurement field at the top left of the
display.
Because the diagnostic MUX points being measured must be in the
range of 0 to ±5 volts, the measurement of some points are scaled to
that measurement range. For example; the +12 Volt reference
( MEAS_12V_REF should measure about +5volts. The –12 Volt reference
( MEAS_NEG_12V_REF should measure about –5 volts. Many of the
voltage measurements are only valid after a number of instrument
settings are changed.
294
S:\agilent\e8285\ALR\Book\chapters\service_scrn.fm
screen, see Figure 9-1 on page
Figure 9-1) selects the desired circuit node for voltage
Figure 9-1 on page
Chapter 8, "Block
for information on how the overall instrument
295.
295, uses the internal